Make The Sale!
This month, Counterman presents one of its more popular annual Features: Counterman's Technical Sales Seminars. As in past years, we again present technical and sales information written to help parts professionals better understand what they are selling and ways to be better at selling them. The Technical Sales Seminars are full of solid technical information and smart sales tips too. What's different this year is the number of product categories we present: nearly two dozen technical sales seminars on a wide variety of parts.
Calipers & Brake Parts
Caliper service is required if a caliper is leaking brake fluid, if a piston is sticking or frozen - or if pads show uneven wear.
Many brake experts recommend rebuilding or replacing the calipers on high-mileage vehicles when the brakes are relined. Like any other mechanical component, calipers wear and corrode with age. Every time the brakes are applied, the back-and-forth motion of the caliper pistons produces a slight amount of wear on the piston seal and piston bore. Moisture contamination in the brake fluid adds to the problem by allowing corrosion to attack the piston bores and the caliper pistons if they are steel or aluminum. As the surface of the pistons and bores become pitted and rough, the seals wear even more and may begin to leak.
As the pads wear, the caliper pistons gradually move outward, exposing more of the piston to potential contamination and corrosion from dust or moisture. If an old corroded piston is then shoved back into the caliper when new pads are installed, the piston seal will be riding on a rough surface. It won't be long before the seal fails and the caliper starts to leak.
Brake fluid leaks are serious because they can lead to brake failure. Brake fluid can also contaminate the brake linings causing the brakes to grab or pull.
Even if a caliper isn't leaking, it's still aging. Rubber piston seals and dust boots lose elasticity with age. Square-cut piston seals help retract the pistons and pads when the brakes are released. If the seals are old and hard, they may not pull the pistons back, which allows the pads to drag against the rotor. When dust boots get old, they often crack or split and allow dirt and water to enter the piston bore area. The result can be accelerated seal wear, piston corrosion and sticking.
Rebuilding or replacing the calipers when the brakes are relined restores the system to like-new condition, improves brake reliability and reduces the risk of leaks.
One thing to keep in mind when selling replacement calipers is the importance of brake balance side-to-side. If only one caliper is being replaced, the replacement caliper should have the same type of piston (steel or phenolic) as the one on the opposite side. Also, if you're selling a loaded caliper assembly, the friction material should be the same as the other side.On low-mileage vehicles, the caliper hardware should be cleaned, inspected and lightly lubricated with a high-temperature, moly-based brake lubricant. Ordinary chassis grease should never be used for this purpose. Badly corroded or damaged caliper hardware must be replaced.
Any caliper that is cracked, damaged, has worn mounting or slide surfaces, elongated pin or guide holes, bore damage or severe bore corrosion must also be replaced.
Repair options include new or reman calipers and loaded caliper assemblies. Loaded calipers are really popular these days because they include everything the technician needs in one box. A loaded caliper includes a new or remanufactured caliper housing, new or reconditioned pistons, new friction pads, plus the shims, bushings or other hardware needed to install the caliper.
Preassembled calipers also help eliminate some of the common mistakes that are often made when replacing calipers, things like leaving off antirattle clips and pad insulators that prevent noise, forgetting to bend pad locating tabs that prevent pad vibration and noise, and reusing corroded caliper hardware that can cause a floating caliper to hang up and wear the pads unevenly.
Other items your caliper customer may need include new brake hoses, brake fluid and special brake tools to bleed the brakes.Loaded calipers are also a good choice for replacing rear calipers on vehicles with four-wheel disc brakes. Overhauling a locking rear caliper is not an easy job because the self-adjusting mechanism inside the piston is difficult to disassemble, clean, lubricate and reassemble correctly. In many instances, the parts are too badly corroded to be reused anyway, and replacement parts may not even be available.
Over 80 percent of all the cars on the road today are front-wheel drive (FWD) with constant velocity (CV) joints on their halfshafts. Many minivans are also FWD, and most four-wheel drive trucks, SUVs and all-wheel drive cars also have halfshafts with CV joints. Thats a lot of CV joints and a huge potential replacement market for both shafts and joints.
CV joints are pretty rugged and will generally go 75,000 to 100,000 miles or more without a complaint. But a number of things can cut a joints normal life expectancy short. The number one killer of CV joints is boot failure. All it takes is a small crack or hole in a boot to doom the joint. Within a few thousand miles, the joint will throw out most of its grease leaving it with little or no means of lubrication. A leaky boot also allows road splash and dirt to get inside and contaminate the joint. Before long the joint is ruined and must be replaced.
The classic symptom of a worn outer CV joint is a clicking or popping noise when turning. The joint usually remains silent when driving straight ahead. Worn inner CV joints act more like a U-joint and may produce a "clunk" or shudder when the vehicle is put into gear or starts to move. Worn inner joints can also cause driveline vibrations that come and go at various speeds.
If a CV joint is making noise or vibrations, it needs to be replaced. If a boot has failed but the joint is still silent, it may only need a boot ∇ provided the grease inside still feels smooth and has not been contaminated with dirt. CV joints can be disassembled for inspection, but doing so requires removing the halfshaft or driveshaft, removing the joint from the shaft, then taking it apart to check the balls, cage and races for wear or other damage.
If a customer only needs a boot, recommend a premium boot that will provide added durability.If a CV joint needs to be replaced, you can offer your customer several options: a new or remanufactured replacement CV joint or a complete shaft assembly with new or reman joints on the ends. Most professional technicians prefer the complete shaft assembly because the shaft is ready to install, saves time and reduces the risk of a comeback.
Selling your customer a complete shaft assembly eliminates the need to change and repack the joints. A complete shaft assembly also reduces the risk of mismatched parts. Many shafts that come with new joints also come with a lifetime warranty.If a customer opts to replace just the joint and not the whole shaft assembly, hell still have to pull the shaft out of the vehicle to change the joint. The opposite joint should be carefully inspected to make sure it is still in good condition before it is returned to service.
Removing a CV joint from the end of a shaft can be tricky on some applications if the joint is held in place with a snap ring. The ring must first be released before the joint can be pulled off the shaft. Others use a circlip, which allows the joint to be tapped off.
Replacement joints usually come with a new boot, special CV joint grease and boot clamps. Ordinary grease must not be used in a CV joint. To install the joint, part of the grease is packed into the joint, and the rest goes into the boot. The boot and joint are then installed on the shaft. Special tools may be required to tighten some types of boot clamps.
On some vehicles, there is no choice as to whether to replace the individual joint or the entire shaft assembly. On vehicles that have "tripod" style outer joints (Toyota Tercel and Nissan Stanza), the joint is part of the shaft, so the entire shaft must be replaced.
Theres a lot of variety in CV joints and shafts, so when looking up a replacement joint or shaft you need to correctly identify the application. This is especially important on older Honda and Chrysler applications, which used shafts from a variety of OEM suppliers. With individual joints, the spline count, diameter and length of the joint must be the same as the original. With shafts, the overall length must also be identical. If the vehicle has antilock brakes and the wheel speed sensor ring is on the outer CV joint, make sure the replacement joint or shaft has the same ring and that the number of teeth match.
Sell the best. It's that simple. When a customer asks for a set of replacement brake pads or shoes, recommend a premium grade product - not the cheapest linings on the shelf.Premium linings outperform standard and economy grade linings in almost every way: more stopping power, longer pad life, better fade resistance and quieter braking.
Premium linings cost more because they are made with superior materials. They also deliver better overall value than economy or standard grade products. Longer-wearing materials extend lining life and push the next brake job thousands of miles further down the road. Better stopping power and fade resistance reduces stopping distances and the risk of an accident. Quieter operation is easier on the ears ∇ and rotors, too.
When you point out the advantages of upgrading to premium replacement linings, most customers will agree and buy the best. Surveys have shown the aftermarket is now selling more premium-grade products than ever before. People are keeping their vehicles longer and are putting more miles on them. The cost of the linings is only a small portion of the labor and other parts that go into a typical brake job, so more people are opting for premium grade linings.Historically, many aftermarket brake suppliers have offered three grades of linings: good, better and best. The least expensive 'value line' economy grade products are targeted primarily at the retail DIY market. These products are strictly for bargain hunters who can't afford a better grade of lining or who don't want to spend a dime more than is absolutely necessary to fix their brakes.
Economy pads are as safe as any other grade of replacement lining, but don't expect them to deliver the same kind of lining life or stopping power as standard or premium linings.
Standard grade or OEM-equivalent linings generally offer similar braking performance and service life as the OE linings on the vehicle. In recent years, the distinction between standard and premium has become blurred because of all of the changes that have been taking place in friction-material technology.
For some time now, brake suppliers have been upgrading their product lines to keep pace with improvements in friction-material technology in new vehicles. 'Application specific' linings whose friction characteristics are modified to more closely match the performance of the OEM brakes they replace are now commonplace. Most premium grade linings are now application specific, but so are many standard-grade linings. What's more, many brake suppliers have introduced new product lines specially designed for trucks, SUVs and import vehicles. Many of these products are premium-grade linings because of their performance and price.
Premium-grade linings, which are the best the aftermarket has to offer, typically are equal to or exceed OEM performance in all categories. Various ingredients are used to enhance the friction materials including ceramics, titanium, copper and a variety of other fibers and materials. Some also have special coatings to help seat new pads and dampen noise. Most premium pads also incorporate such features as chamfers, slots and special shims to control noise and vibrations.
Some premium pads are also 'preburnished' to eliminate many of the problems that can occur if the pads are not broken in properly. When brake linings are manufactured, the resins that bind the ingredients together are not fully cured. When the linings are later installed on a vehicle, the heat produced by normal braking bakes the linings and cooks out the residual chemicals from the resins to improve the friction characteristics of the lining. But if the brakes get too hot before the linings are fully cured, it can 'glaze' the linings causing noise and performance problems. To eliminate the need for a break-in period, some brake suppliers now add an extra manufacturing step to fully heat-cure (burnish) the linings.
Good brakes are absolutely essential for safe driving. When the brakes are relined, the goal should be to restore the entire brake system to good-as-new or even better-than-new condition - not just to replace the worn linings and nothing else. Installing premium linings can help accomplish that goal, as can inspecting the entire brake system and replacing any other parts that are worn, damaged or out of specifications.
The condition of the rotors is especially important, too. Rotors that are rough or have too much runout must be resurfaced to restore the friction surface for the pads. Rotors that are worn to minimum thickness specifications, have hard spots, cracks or other damage must be replaced. If a customer needs new rotors, recommend premium rotors. Economy rotors do not have the same metallurgy as premium rotors, nor the same manufacturing tolerances. As a result, economy rotors may be noisier, wear faster and/or increase the distance required to stop the vehicle.
Most all parts store move a lot of friction material off their shelves. Knowing what questions to ask and being able to communicate the specific differences between the various lines and grades of brake pads will help your counter staff be better at selling this important item. And since brakes are a safety-related product, many customers are less resistant to a suggestion to upgrade to a higher-quality pad.
Ball joints have been around since the 1950s, but that doesn't mean they haven't changed with the times.Ball joints have become more sophisticated and more important in terms of good steering return, steering feel and handling. The traditional steel-on-steel ball joints began to change in the 1970s. To reduce friction for improved steering return and better overall ride quality, ball studs were made smoother, and new types of bearing materials were introduced.
In the 1980s, low-friction ball joints with polished ball studs and polymer bearings came into widespread use on a variety of vehicle applications, including European and Japanese imports, domestic front-wheel drive passenger cars and even trucks. At the same time, joint seals and boot materials were improved to eliminate the need for grease fittings in many instances. Many premium joints now use urethane rather than neoprene or synthetic rubber boots.
Steel-on-steel ball joints are still available for many older vehicle applications and work just fine. But on newer vehicles, it's important to use low-friction ball joints. Replacing one type with another may cause a noticeable increase in steering effort and harshness, and it may also reduce steering return.
Ball joints are classified according to their location or function in the suspension. There are upper and lower ball joints. Short and long arm (SLA) suspensions have two uppers and two lowers, as do wishbone strut suspensions. Ordinary MacPherson strut suspensions only have two lower joints.
Some ball joints are load carrying, while others are not. The loaded variety may be compression joints or tension joints. Compression joints carry loads that bear down on the ball stud. So, most joint wear occurs where the ball stud presses into its bushing. This type of joint is found in SLA suspensions where the spring is mounted over the upper control arm. Tension joints, by comparison, carry loads that try to pull the joint apart. Wear occurs in this joint at the point where the shoulder of the ball stud pulls against its seat. The lower ball joints on SLA suspensions, where the spring sits on the lower control arm, are tension joints. Tension joints are also found on modified MacPherson strut suspensions (Mustang, T-Bird and Camaro/Firebird) where the spring sits on the lower control arm rather than on the strut.
Other suspension parts that may also need to be replaced include tie rod ends, idler arms, suspension bushings, shocks or struts. And don't forget grease if the joints are the type that have grease fittings.Ball joints that are not loaded include the upper joints on SLA suspensions where the spring sits on the lower arm, the lower joints on suspensions where the spring is over the upper control arm and the lower joints on MacPherson strut suspensions where the spring is around the strut.
All types of ball joints need to be replaced if wear exceeds factory limits. Inspection procedures and specifications vary from one application to another, so it is important to refer to a ball joint specification chart for the particulars.
Many load-carrying tension-type lower ball joints on General Motors and Ford rear-wheel drive applications have a built-in wear indicator to show how much wear has taken place inside the joint. This same type of joint is also used in the rear suspension on some of GM's big front-wheel drive cars (Cadillac, Buick and Oldsmobile). Load carrying ball joints usually wear faster than unloaded counterparts. Consequently, the lower ball joints on an SLA suspension typically wear out before the upper joints. Symptoms of worn ball joints include front wheel shimmy at low speed, steering wander, clunking noises from the front suspension and camber (shoulder) wear on the front tires.
When one joint is badly worn, chances are its companion joint on the opposite side will also be worn or near the end of its service life. The other joint may still be marginally within specifications, but for how much longer is anybody's guess. Replacing both joints at the same time can save the vehicle owner some down time and future inconvenience.
Some ball joints are difficult to replace because they are pressed into the control arm. If your store has a hydraulic press, you can offer this service to your customers. Other joints may require the removal of mounting rivets or the complete replacement of the control arm, which means your customer may need additional tools (bushing tools, ball joint separator, etc.) to replace the joint.
Contrary to popular belief, the strongest distributors are not necessarily traded on Wall Street.Exhaust system parts include more than just mufflers, pipes and cats. An important component of the exhaust system are the exhaust manifolds that route the hot exhaust gases into the rest of the system.
Exhaust manifolds are hot exhaust products these days thanks to lean fuel mixtures, lighter-weight OEM castings, welded tubular steel manifolds, an aging vehicle fleet and good old wear and tear. Exhaust manifolds can fail for the same reasons as any other exhaust component. Heat, thermal stress and corrosion can produce cracks that result in leaks and noise.
Exhaust manifolds are not replaced as often as mufflers, pipes or even converters, but when a customer needs one, youve got to have a product line you can offer. New aftermarket replacement manifolds are available for a wide variety of popular engines even some that arent so popular but that have a high incidence of failure. Two of the most common applications for replacement exhaust manifolds are 302 V8 Ford pickup trucks and 350 V8 Chevy trucks. People drive old pickups forever, but the manifolds often dont go the distance. Another application is the exhaust manifold for 1987-90 Jeeps with the 4.0L engine. These are also a good mover.
Heres a related sales item: motor mounts. Loose or broken motor mounts will allow the engine to move excessively. This can increase the strain on the exhaust system parts that may lead to metal fatigue, cracks and exhaust leaks. When a manifold cracks or warps and loses its ability to hold a tight seal against the cylinder head, exhaust escapes into the engine compartment. The hot gases can burn nearby wires and hoses, causing additional problems. Worse yet, carbon monoxide vapors may find their way into the passenger compartment with potentially deadly results.
The first sign of trouble may be a whistle, a sputter or a roar from the engine compartment signaling an exhaust leak at the manifold. Sometimes the leak will be blamed on the exhaust manifold gasket if no cracks in the manifold are visible. But if the mating surface of the manifold is no longer flat due to heat distortion, the manifold will have to be resurfaced or replaced.
Pipe hangers and heat shields should be inspected to make sure none are broken, loose or missing.If a manifold has cracked or a bolt ear has broken off, some people will attempt to find a cheap replacement at a salvage yard. Good luck, because many manifolds that end up in salvage yards are only good for scrap iron. New aftermarket replacement manifolds are not that expensive, and theyll provide years of service something which cant always be said for used manifolds.
Another advantage offered by some aftermarket manifolds is an improved design. If the OEM manifold has a thin spot or weakness that leads to cracking and failure, the aftermarket manifold may be redesigned to improve the manifolds crack resistance and durability.
Some aftermarket suppliers also offer reconditioned exhaust manifolds. These are used manifolds that have been inspected, cleaned to remove rust and scale, and resurfaced to ensure a leak-free installation.
In addition to the manifold itself, your customer will also need new manifold gaskets and possibly any air-related plumbing (if so equipped) for the smog control system. You should also recommend new fasteners for the manifold. Reusing old rusty, corroded bolts is asking for trouble and a poor seal.
Replacing an exhaust manifold can be a time-consuming job if access is limited or the manifold is buried under other components. Your customer should use this opportunity to inspect the rest of the exhaust system to see if anything else may need to be replaced, too.
The catalytic converter, pipes and muffler all need to be carefully inspected for leaks or damage. If corrosion has gotten the upper hand, your customer may need a whole new exhaust system.Head pipes, particularly those on front-wheel drive cars and minivans with transverse-mounted engines, are subject to a lot of flexing as the engine rocks back and forth. Many import cars use a special flex pipe section in the head pipe to handle these motions. The flex pipe often cracks and leaks, so it may also have to be replaced.
WHEEL BEARINGS & HUBS
When auto makers started using sealed wheel bearings back in the 1980s, many technicians thought wheel bearing service was a thing of the past at least for newer vehicles.True, sealed bearings don't need any maintenance or adjustments, but that doesn't mean they last forever. Like any moving part on a vehicle that is subject to wear and contamination, wheel bearings can and do wear out.
The first symptom of wheel bearing trouble is usually noise a rumbling, growling, chirping or cyclic noise from the vicinity of the wheels is a good indication that the bearings need to be inspected without delay.
Wheel bearing noise is usually proportional to vehicle speed and does not change when accelerating, coasting or decelerating (which distinguishes it from differential, transmission or U-joint noise). The noise may change when turning, or become louder or even disappear at certain speeds. But it shouldn't be confused with the clicks and pops produced by a worn outer CV joint on a FWD car. A bad outer CV joint usually only makes noise when turning, not when driving straight ahead.
If a sealed bearing assembly is noisy or feels rough when the wheel is spun by hand, the bearing and hub assembly needs to be replaced.
When looking up the replacement unit, you may have to ask your customer whether or not the vehicle is equipped with antilock brakes. On some cars with ABS, the wheel speed sensor is part of the wheel bearing and hub assembly.
On older vehicles with serviceable wheel bearings, the bearings and races must be removed, cleaned, inspected and repacked with grease every 30,000 miles or according to the recommended service intervals. The bearings should also be inspected if the vehicle is experiencing steering looseness or wander, or if the bearings are making noise or feel rough when a wheel is spun by hand.
If the rollers, balls or races are worn, pitted, cracked or show any damage, replacement is required. These types of wheel bearings and races must always be replaced as a matched assembly.The bearing hub bore should also be inspected for damage and proper bearing fit. Heat discoloration of the bore or bearings would indicate loss of lubrication or overtightening. If the bore is damaged or does not hold the race snugly, your customer will need a new hub, rotor or drum.
Spindles on rear-wheel drive vehicles also need to be inspected for straightness, damage or cracks.
Customers who own boat trailers and other utility trailers should also pay close attention to the wheel bearings on their trailers especially if the wheels are in water frequently. Bearings on boat trailers should be cleaned, inspected and repacked annually.When serviceable wheel bearings are repacked or replaced, new grease seals must also be installed. Reusing old grease seals is risky because they are easily deformed during removal. Grease leaking past an old seal can contaminate the brake linings and increase the risk of bearing failure from the loss of lubrication.
Wheel bearings require special high-temperature grease such as #2 NLGI lithium-based grease or a synthetic wheel bearing grease. Ordinary chassis grease must never be used to lubricate wheel bearings. Make sure your customer gets the correct type of grease. No grease or maintenance is required for sealed wheel bearing and hub assemblies.
Serviceable wheel bearings must be adjusted after they have been installed to achieve the proper clearances or preload. Sealed wheel bearing and hub assemblies are preset at the factory and require no adjustments.
If serviceable wheel bearings are not adjusted correctly, they may cause steering problems and/or fail prematurely. Tapered roller bearings on the front of RWD vehicles are never preloaded. They're snugged up with no more than 15 to 20 ft. lbs. of torque while rotating the wheel to make sure the bearings are seated. Then the adjustment nut is loosened 1/6 to 1/4 turn, and locked in place with a new cotter pin. As a rule, end play should be about .001 to .005 inch. On FWD cars, the front bearings typically have zero play or a slight preload. Too much play can allow steering wander, which may be mistaken for worn steering components or the need for an alignment. Bearings should be adjusted according to the manufacturer's specifications.
Don't forget to ask about special tools, too. Some bearings can be difficult to remove and may require a special hub puller for disassembly and/or drivers to install the new bearings.
Alternators are a hot selling product today because the electrical loads in today's vehicles are higher than ever before. Aany alternators put out nearly twice the amperage that was commonly required only a decade ago. Even so, the combination of higher loads and hotter underhood temperatures often proves lethal. Consequently, alternator sales are up.
The rising popularity of high-powered aftermarket sound systems has also created a booming market for high-output alternators. It takes a lot of amps to keep the subwoofers throbbing on many of these systems, more than many standard alternators can produce. Several aftermarket suppliers now offer special replacement alternators for extreme audio applications that crank out more amps to keep the decibels flowing. Some units are rated up to 200 amps, which is nearly double that of the stock alternator they replace. The higher outputs are achieved by beefing up the stators with more windings and reducing the air gap between the stator and rotor to boost efficiency.
Recommend a high-output, "police-special" alternator for these kinds of applications. Like the alternators designed for extreme audio applications, alternators designed for high-load emergency vehicles feature special heat-resistant construction that is far superior to the parts used in a typical reman or even a new alternator. The most common applications include the Ford Crown Victoria and Chevy Impala.To handle the heat, some of these units have housings plated with high-temperature ceramic coatings. Stators may also be wound with Nomex insulation, the same kind of heat shielding used in flame-resistant clothing. Soldered connections are coated with silicone to reduce corrosion and protect against heat and vibration, and high-temperature diodes are used for maximum durability.
Another trick that helps boost the amps is a smaller diameter pulley. Reducing the size of the pulley increases the rpm of the alternator at idle so it can produce more amps.
These special high-output alternators for extreme audio applications cost more than standard alternators, but when you consider what it costs to replace one stock or reman unit after another because they can't take the heat, a high-output alternator is well worth the bucks.
The same goes for many police car applications. Squad cars are alternator killers too. Most of these vehicles are constantly on the go or sitting for prolonged periods of time with the lights, heater or air conditioner and communications equipment running. The emergency lights alone can suck up to 85 amps from the alternator, which is a heavy load. That's why alternators in police cars typically last only about a year or so.
For your average customer, you can offer him a new or reman product. Even in these applications, overloading is a common cause of premature alternator failure, especially in heat-sensitive, high-output units such as Ford IAR and Delco CS Series alternators. For these kinds of applications, a high-quality replacement product is essential.Some electrical rebuilders cut costs by reusing old bearings, slip rings and other parts that should probably be replaced. Some only polish the slip rings, which can cause the brushes to bounce if the rings are out of round. This creates electronic noise that may interfere with the operation of other onboard electronics. Voltage regulators, rectifiers and diodes should be tested and replaced as needed to assure reliable operation. Ask your electrical suppliers what parts they typically replace and what kind of warranty they offer. Then recommend the best products to your customers.
Bench testing a customer's old alternator in your store can help determine its condition and eliminate unnecessary warranty returns. Many "defective" alternators work perfectly when bench tested, so the problem is obviously elsewhere in the electrical system. Helping your customer sort out these problems before he replaces the alternator can save everyone a lot of trouble.Other points to keep in mind: replacement alternators should always have the same or higher amp rating as the original; the battery should always be tested and fully recharged before the replacement alternator is installed; both battery cables should also be cleaned and inspected and replaced if loose or defective; and always recommend a new drive belt.
Summer is almost here, and as temperatures rise so will the demand for replacement A/C parts.The compressor is the heart of the refrigeration circuit. It pumps and pressurizes the refrigerant to move it through the system. Compressors work hard and run hot, up to several hundred degrees and several hundreds of pounds per square inch of internal pressure. They rely on a few ounces of lubricant to keep their parts moving. If the lubricant is lost because of a leak, or if it breaks down due to contamination, the compressor won't last. Sooner or later, the compressor will fail.
A compressor failure is bad news for the entire A/C system because it often spews metallic debris into the condenser. From here, the debris can travel to the orifice tube or expansion valve and cause a blockage. If not removed, debris can also find it's way back to a new replacement compressor and cause it to fail, too.
Depending on the type of condenser, flushing with a chemical approved for this purpose may or may not remove all of the debris and other contaminants. Older serpentine-style tube-and-fin condensers can often be flushed successfully, but parallel-flow condensers are very difficult to clean. So too are newer-style condensers with extremely small extruded tubes. For these kinds of applications, the condenser should be replaced following a compressor failure. Condenser replacement would also be recommended if the A/C system is found to be contaminated with sludge.
Either way, when a compressor is replaced, the accumulator or receiver/dryer should also be replaced. This device contains desiccant that traps moisture and acts as a filer to protect the system. A new orifice tube should also be installed because the small hole in this metering device can become easily plugged. An inline filter can also be installed after the condenser for added protection and should always be used if a system has been flushed.
Replacement compressors may or may not contain lubricant from the factory. In some cases, the shipping oil must be drained before the compressor is installed. In other cases, the compressor may contain a POE or PAG lubricant that should be compatible with the vehicle's requirements. Advise your customer to follow the compressor supplier's installation instructions to the letter to avoid warranty problems later.
If a condenser needs to be replaced because of damage or contamination, the replacement must have the same or better thermal efficiency as the original. If not, it may cause a noticeable drop in cooling performance. Installing a new condenser with a higher thermal rating can improve cooling performance, and it may be required when retrofitting (converting) some older R-12 A/C systems to R-134a.The evaporator is another heat exchanger in the A/C system that may need to be replaced, usually because of internal corrosion that creates a refrigerant leak. The evaporator's job is to cool the air as it enters the passenger compartment. It is the coolest part of the A/C system, so moisture tends to collect there and cause corrosion. Evaporator leaks are hard to find because of the unit's hidden location. Leak detection dye which is commonly used to find leaks in other parts of the system isn't much help there, so leaks are usually found using an electronic leak detector with a long nose probe.
Another problem that can affect evaporators is odor. The dark, wet environment inside the HVAC unit is ideal for breeding odor-causing bacteria and fungi. Some evaporators have a special coating that inhibits the growth of these organisms. For those that don't, a spray treatment with a germ-killing chemical will usually get rid of the odor.
A customer who is buying A/C parts will also need refrigerant and compressor oil. R-12 is no longer being manufactured in this country, so when an older vehicle requires major A/C repairs, the A/C system is usually converted to R-134a.
Compressor lubricant requirements vary depending on the application, so make sure your customer gets the correct type of oil. The wrong oil will void the manufacturer's warranty and probably lead to premature compressor failure. Older R-12 systems use mineral oil, but most newer vehicles use a specific viscosity of PAG oil. POE oil is often used for retrofits.
A good battery is an absolute must for reliable starting.A low battery, old battery or a battery with corroded terminals or loose connections may not provide enough amps to crank the engine. Low battery voltage can also upset the operation of onboard electronics and other electrical accessories on a vehicle.
When a customer comes to you for a new battery, the first thing you should ask him is why he thinks he needs one. If his battery has run down because he left the lights on, the battery may only need to be recharged. Or, if it ran down for no obvious reason, his vehicle may have a charging problem.
Average battery life varies depending on the climate, but on average it is about four years. In hot climates, it may only be three years. In mild climates, it may be five years or longer. So if a battery is getting old, it may be near the end of its useful service life.
For motorcycle, lawn and garden tractors and similar small engine applications, follow the catalog recommendations for choosing the correct replacement battery.As a battery ages, it loses some of its capacity to accept and hold a charge. Cell plates become sulfated and eventually reach a point where they don't have enough active surface left to deliver the amps and voltage needed to operate the vehicle. This process can be accelerated if the battery is run down and allowed to remain in a discharged condition for a long period of time. Lead-acid batteries must be kept at or near full charge to prevent premature failure.
Vibration, physical damage and/or loss of electrolyte can also be causes of battery failure. A broken electrical connection between cells or a shorted cell plate can kill an otherwise good battery.
To determine a battery's true condition (regardless of its age), the battery's state of charge and ability to deliver amps should both be tested. State of charge tells you if the battery is run down or not. If the vehicle's charging system is functioning properly, the battery should be 75 percent or more charged. The level of charge can be tested with a digital voltmeter (12.4 volts or higher is a good reading), or with a hydrometer if the battery has removable caps (a temperature corrected specific gravity of 1.225 or higher indicates a 75 percent charge level.)
Testing the battery's ability to deliver amps can be done with a carbon pile load tester (this requires recharging the battery first to get an accurate reading), or an electronic tester that measures the battery's conductance (which does not require recharging first.) In both cases, the battery's Cold Cranking Amp (CCA) rating is used to determine the test load on the battery and its performance. If the battery tests good, it can be recharged and returned to service. But if it tests bad, it's time for a new battery.
Once you've identified the correct group size for your customer's vehicle, you can discuss replacement battery options. How long of a warranty does he want? How much cranking power does he need?
The CCA rating of a replacement battery should be the same or a little higher than the original. Batteries that have extremely high CCA ratings (up to 1,000) are a good choice for unusually cold climates, but may sacrifice battery life and durability to achieve such high numbers. For most applications, 500 to 650 CCA amps is all that's required.
Depending on the brand of batteries you stock, you may also have several different technologies to offer your customer. The traditional lead-acid battery with liquid electrolyte (acid) inside is still the most common design. But some batteries now have Absorbent Glass Mat (AGM) construction and use a gel electrolyte that is spill-proof. Some batteries also have a unique spiral wound construction with cylindrical cells rather than flat plates that increase durability and power efficiency.
If a customer needs a battery for a boat or other high-drain application, a marine battery is what he needs, not an ordinary car battery. Marine batteries are designed for deep discharge cycles.When you sell a customer a battery, test it before it leaves the store to make sure it is fresh and fully charged. This can prevent unnecessary comebacks later. Also, advise your customer to inspect and clean the battery cables, and replace any that are badly corroded or damaged. The battery must also be held securely in place with a holddown bracket.
BELTS & HOSES
Would you believe that nearly a third of all cars and light trucks have belts and/or hoses that need to be replaced?This percentage is based on real-world vehicle inspections conducted by the Car Care Council. In most instances, the vehicle owners were unaware of the poor condition of their belts and hoses.
Everybody wants a reliable vehicle to drive, but not many people are forward-thinking enough to practice preventive maintenance by replacing aging belts and hoses before they fail. Most never replace a belt or hose until it has obviously failed or is causing a problem.
A belt that is glazed, frayed, cracked, oil-soaked or squealing is a belt that needs to be changed. The same goes for any hose that is leaking, cracked, bulging, feels hard or mushy, or is chaffed.
Replacing belts and hoses every four or five years can greatly reduce the risk of a breakdown.
Most belts and hoses fail from the inside out. Rubber hoses, made of neoprene and other synthetic materials, deteriorate with age and exposure to heat. The hose material can become hard and brittle. Tiny cracks develop in the rubber, that eventually cause the hose to split, blister or leak. Oil on the outside of coolant hoses can also accelerate the breakdown of the hose material. This type of deterioration can usually be seen on the outside. But what often escapes detection is what's going on inside hoses.
Belts deteriorate as they age. Every time a belt passes around a pulley, it bends and flexes. This produces heat in the belt that hardens the rubber over time. The wear process can be greatly accelerated if the belt is loose and slips. The additional friction between belt and pulley will make a belt run even hotter. After millions of such journeys around the pulleys, even the best drive belt begins to suffer the effects of age. The rubber begins to crack and fray, and the internal cords become weakened and brittle. Eventually, the belt breaks, and all cooling is lost along with whatever other functions were powered by the belt (water pump, alternator, power steering, air conditioning, etc.)
One problem that's guaranteed to shorten the life of any belt is slippage. Slippage creates heat that glazes and hardens the belt, making it more prone to cracking and premature failure. The symptoms of slippage are noise or chatter and glazed or shiny sidewalls on the belt.
A loose belt should be retensioned back to the manufacturer's specs using a tension gauge. The old rule of thumb about leaving a half inch of deflection between the two furthest pulleys is not very accurate, and unless a gauge is used, there's no way to know if the belt is too tight or not tight enough. Too much tension on the belt increases strain on the tensile cords, which shortens belt life as well as the life of the shaft bearings on the accessories.
Many engines today have automatic tensioners to keep the serpentine belt tight. If the spring inside the tensioner has become weak or the tensioner has reached its travel limit, it won't be able to maintain proper belt tension.
Replacement V-belts and serpentine belts must be the same length and width as the original. If the engine has a serpentine belt with an automatic tensioner, the tensioner should be checked to make sure it is working properly. A new tensioner is needed if the old one is weak, sticking or badly corroded, or if the bearings are loose or making noise. The same goes for any idler pulleys on the engine.
Replacement hoses must be the same diameter and length as the original. Molded hose may have to be trimmed to length depending on the application. New clamps should always be used.
Branched hoses should be replaced entirely rather than patched. If one part of the hose has failed, chances are the rest of the hose is rotten too.
Additional products your customer may need when replacing radiator or heater hoses include antifreeze, a new thermostat housing and an inline fitting for flushing the cooling system.
Other items that may be needed when replacing a head gasket include coolant, oil, filters, spark plugs and additional gaskets for the intake and exhaust manifolds and valve covers. Other hoses that may also need attention include fuel, vacuum and emission hoses. Replacement hose for these applications must be the same type as the original to resist pressure, vacuum and/or chemical attack. These types of hose are often sold by the foot and must be trimmed to length.
Contrary to popular belief, the strongest distributors are not necessarily traded on Wall Street.Filters are maintenance items and must be replaced periodically according to recommended service intervals ∇ or as needed depending on operating conditions.
Air filters keep dirt and abrasives out of the engine. Even the tiniest particles can cause ring and cylinder wear if they find their way inside the engine. For every gallon of fuel thats burned, the average engine consumes about 10,000 gallons of air. So its important to keep the incoming air as clean as possible.
The OEM-recommended replacement interval for air filters is typically 30,000 to 50,000 miles for many vehicles today. But how often the filter really needs to be replaced depends on the environment in which the vehicle is driven. Dusty gravel roads are the worst, but even a dirty urban environment can plug up a filter quickly. The air filter should be inspected every time the oil is changed (every three to six months) and replaced as needed.
Another type of air filter that needs to be changed periodically is the cabin air filter on newer vehicles. The cabin air filter traps dirt, allergens and odors before they enter the passenger compartment. The filter may be located behind the glove box, under the base of the windshield or in the HVAC unit. The recommended replacement interval is typically 30,000 miles.
The oil filter protects the engine against wear particles and dirt. Oil flows though the filter before it goes to the bearings so the filer can trap any debris that might harm the engine. Most of the contaminants are extremely small: on the order of five to 40 microns (millionths of an inch).
Other items that may be needed when replacing a head gasket include coolant, oil, filters, spark plugs and additional gaskets for the intake and exhaust manifolds and valve covers. The oil filter should be replaced every time the oil is changed, which is every three to six months, or 3,000 miles, which ever comes first. If the filter is not changed often enough and becomes plugged, it may restrict oil flow to the engine or allow unfiltered oil to bypass the filter. Either way, engine damage may result.
The fuel system is protected by two filters. Inside the fuel tank is a filter screen on the fuel pickup tube. The purpose of this screen is to keep debris out of the fuel pump and fuel line. But the screen is relatively coarse and does not stop smaller particles that can clog the injectors or contribute to internal engine wear. This job is handled by an in-line fuel filter, which may be located under the vehicle or in the engine compartment.
The fuel filter is often neglected because many vehicles today do not have a recommended replacement interval for this vital component. Even so, many experts recommend replacing the filter every two years for preventive maintenance. The filter should also be replaced if a new fuel pump or injectors are being installed. A plugged fuel filter can cause fuel starvation, lack of high-speed power and stalling. If a plugged fuel filter is full of rusty sediment, the fuel tank may also have to be replaced to prevent the same thing from happening again.
Another important filter is the PCV breather filter. This filter is used on some engines to clean the air before it enters the crankcase. It may be located inside the air filter or a cap on a valve cover. The recommended replacement interval is typically the same as for the PCV valve, which is every 50,000 miles.
The transmission is another component that requires the protection of a filter. Many newer vehicles have no recommended service interval for changing the transmission fluid or filter. The latest generation of automatic transmission fluids (ATFs) have increased oxidation resistance for improved longevity. Even so, that doesnt mean the fluid and filter will last forever. The fluid still becomes contaminated with friction debris from the clutch packs and metallic particles from bearings and gears. The filters job is to trap this debris so it doesnt cause additional wear or gum up the control valves.
The transmission filter should be replaced when the fluid is changed, which many transmission experts recommend doing every two to three years or 24,000 to 36,000 miles. Replacing the filter requires dropping the transmission pan, which will require replacing the pan gasket, too.
Identifying the transmission application may require more than the year, make and model. You may also need the engine size and transmission type. Many trannys are identified by the shape of the pan gasket and/or an OEM ID number on a plate attached to the transmission or transaxle. If youre not sure, compare the old and new pan gaskets to make sure they match. Do the same with the filters.
When it comes to maintaining peak engine performance, fuel economy and emissions, nothing is as important as the spark plugs. The spark that jumps across the gap between the plug's electrodes ignites the fuel mixture and releases the explosive power in the fuel. If there's no spark or the spark is too weak to ignite the fuel, the engine misfires, looses power, wastes fuel and pollutes.
Misfires are bad news because unburned fuel passes right through the engine and into the exhaust. This increases emissions and also causes the catalytic converter to run hotter than normal. A really bad misfire may even damage the converter.
Every engine misfires occasionally, but if the spark plugs are worn or fouled, or the ignition system can't deliver enough voltage for reliable ignition, misfires may cause hard starting, rough running, hesitation, increased fuel consumption and elevated hydrocarbon (HC) emissions. It doesn't take many misfires to make a vehicle fail an emissions test.
One way to prevent misfires is to make sure the engine has a good set of spark plugs. These can be standard plugs, long-life plugs or performance plugs. As long as they produce a hot, reliable spark, ignition misfire shouldn't be an issue.
To minimize the risk of misfire and maximize ignition performance, today's spark plugs are designed to resist fouling and wear under a wide range of operating conditions. Improvements in electrode alloys allow many plugs to now last up to 100,000 miles. With conventional plugs, the recommended replacement interval is typically 45,000 miles.
Spark plugs need to be changed periodically because of wear and fouling. Every time a spark plug fires, a microscopic amount of metal is lost from the electrodes. As the miles add up, the electrode gap grows wider and wider increasing the voltage required to create a spark. Eventually the point is reached where the ignition system can no longer provide enough volts to fire the plug resulting in a misfire.
Fuel residue and oil ash also build up on spark plugs. Normally, the plugs get hot enough to burn off the deposits, but with frequent short-trip driving, the plugs may not stay hot enough long enough to burn off all the deposits. This can allow deposits to build up and interfere with the spark causing misfires.
Spark plug manufacturers have succeeded in extending the life of spark plugs and fouling resistance by going to high-temperature electrodes made out of platinum, iridium and other exotic metals. Platinum is one of the best conductors of heat and electricity. It also resists chemical corrosion and electrical erosion much better than ordinary steel alloys, making it an ideal material for the electrodes in long-life spark plugs. Iridium is even better. Iridium is six times harder and eight times stronger than platinum. This allows the use of a smaller center electrode, which reduces the voltage required to fire the plug by as much as 5,000 volts compared to a standard spark plug.
Spark plug manufacturers also use a variety of different electrode configurations to reduce misfires by exposing more of the spark and flame kernel to the fuel mixture inside the combustion chamber. Extended electrodes, surface gap electrodes, multiple electrodes and specially-shaped outer electrodes are all different techniques that are used to improve ignition performance and reliability.
Replacement spark plugs can be any brand and almost any type as long as the thread diameter and length, seat type, electrode reach and heat range are correct for the engine application. Follow the spark plug manufacturer's recommendations for replacement plugs.
Upgrading from conventional spark plugs to long-life plugs can reduce the need for future maintenance and lessen the need to change plugs as frequently on vehicles where plug access is difficult (like the back plugs on FWD cars and minivans with transverse mounted engines). Today's tight engine compartments don't leave much elbow room for changing plugs on many V6 and V8 engines, which is one reason why the OEMs have mostly gone to long-life 100,000-mile spark plugs. The other reason is to reduce the risk of misfires, emission failures and possible converter damage caused by worn or fouled spark plugs.Plugs in engines with aluminum cylinder heads should not be changed until the engine has cooled. Also, care must be used when tightening the plugs so as not to strip the threads in the head.
The condition of the spark plug wires is also important. Wires that are damaged, cracked, loose or exceed resistance specifications must be replaced to assure a hot, reliable spark.
Theyre round, flat and very heavy and no engine would run very smoothly without one.A cast iron or steel flywheel is mounted on the end of the crankshaft to maintain the momentum of the crankshaft between power strokes, to store energy and to help smooth out variations in the speed of the crankshaft.
On engines that are externally balanced, the flywheel is also used to maintain engine balance. This type of flywheel typically has a large recessed area on a portion of the side that faces the engine. The offset mass acts as an additional counterweight for a V6 or V8 engine.
The flywheel is also part of the starting system. The starter motor drive engages a toothed ring around the outside circumference of the flywheel. On some engines, the flywheel also has notches that provide timing signals for the crank position sensor. These signals are used by the PCM to control ignition timing and fuel injector timing.
On vehicles equipped with manual transmissions, the flywheel also supports the clutch. The face of the flywheel provides a friction surface for the clutch disk and also conducts heat away from the clutch. The friction surface may be flat or recessed into the flywheel.
When looking up a replacement flywheel for a customer, youll need the engine and drivetrain in the vehicle in addition to the year, make and model. On some applications you may need a VIN number or casting number if there was a running mid-year change in the flywheel.There are also dual mass flywheels that combine two flywheels into one. These are used on late-model Ford pickups with 6.9L and 7.3L diesel engines as well as some luxury European imports. The primary flywheel is attached to the crankshaft and the secondary flywheel supports the clutch. The two are joined by damper springs, friction material and ball bearings. This arrangement acts like a filter to dampen engine variations in engine torque and vibrations for quieter, smoother operation. It also cushions the rest of the drivetrain from sudden shock loads and reduces harshness.
Because of its hard-to-reach location inside the bellhousing, a flywheel receives little attention unless theres a starter problem or the clutch needs to be replaced. Damaged or broken teeth on a flywheel can prevent the starter drive gear from engaging consistently, preventing the engine from cranking. The only cure here is a new flywheel.
If a clutch is being replaced, the flywheel must be inspected for excessive wear, warpage, runout, hard spots, heat checking and cracks. Most clutch manufacturers recommend resurfacing the flywheel to restore the friction surface to like-new condition.Minor wear, small imperfections, and heat checks can often be removed by resurfacing. But flywheels in some late-model cars may not be thick enough to allow much resurfacing. Large cracks in a flywheel are extremely dangerous because they weaken the flywheel and may cause it to explode at high rpm. A cracked flywheel must be replaced.
If a stepped flywheel is resurfaced, equal amounts of metal must be removed from the recessed face as well as the edge that mounts the clutch to maintain proper clutch clearances. With dual-mass flywheels, resurfacing is not recommended on BMW or Porsche. A dual-mass flywheel may also have to be replaced if the friction linings or springs inside have failed. Some aftermarket suppliers have less-costly conventional solid replacement flywheels for vehicles that were originally equipped with a dual-mass flywheel. One can be substituted for the other, but some customers may find the increase in noise, vibration and harshness objectionable. On the other hand, a one-piece solid flywheel is considerably less expensive, simpler and more reliable.
Watch out for engine swaps on older vehicles. If someone has replaced an internally balanced engine with an externally balanced engine (or vice versa), make sure you get the correct type of flywheel for the engine. Installing a regular flywheel on an engine that is externally balanced will cause serious vibrations.New flywheels often have a protective factory coating to inhibit rust. This should be removed by washing the flywheel before it is installed. New crankshaft bolts are also recommended and a pilot bushing if one is used. Crankshaft bolts must be torqued to specifications to assure proper flywheel alignment and retention. Runout should also be checked with a dial indicator to check for a bent crankshaft flange.
Engines need a head gasket to seal the combustion chambers, control coolant flow between the cylinder head and block, and prevent oil and coolant leaks.Head gaskets can only be used once, so if the cylinder head is removed from an engine for any reason, your customer will need a new head gasket set. Hell also need a new gasket if the old one is leaking oil, coolant or compression.
Head gaskets can fail if: an engine overheats or has a detonation problem; if the gasket is not installed correctly (incorrect bolt torque, wrong tightening sequence; or head and block surface too rough, dirty, scratched or out-of-flat).
On late-model bimetal engines with aluminum heads and cast iron blocks, some head gaskets fail because aluminum expands at a faster rate than cast iron when it gets hot. This creates a back-and-forth scrubbing motion that can shear some gasket materials. To keep the gasket from sticking, many late-model engines have head gaskets with low-friction coatings and are made of graphite which has natural lubricity and excellent thermal properties. On other applications, the durability of the head gasket has been improved by using a new type of construction called Multi-Layer Steel (MLS).
MLS gaskets are made of several layers of steel (typically three to seven). The outer layers are usually stainless spring steel and have embossing (raised beads) to improve sealing. The outer layers are also coated with a thin layer (.001 to .0015 in.) of nitrile rubber or Viton to provide extra cold sealing. The inner layers of an MLS gasket are flat and provide added support and thickness.
The multi-layer, all-steel construction makes MLS gaskets very durable and highly resistant to burn-through. The gaskets also retain torque well and wont take a compression set like some composition gaskets. The design also requires less clamping force on the head bolts, which reduces bore distortion for reduced blowby and emissions. But MLS gaskets are also very expensive to manufacture and require an extremely smooth mirror-like finish on both the cylinder head and engine block. Both surfaces must also be as flat as possible.
To achieve proper loading, most MLS gasket applications also require a special type of head bolt called a torque-to-yield (TTY) bolt. TTY head bolts are typically longer and narrower than ordinary head bolts and stretch slightly when tightened. Most vehicle manufacturers say TTY head bolts should only be used once and should always be replaced with new TTY bolts when the head gasket is changed.
If new head bolts are not included in a head gasket set, be sure to recommend them to your customer.
Tough as MLS gaskets are, they cant be reused. Once installed, the embossed surfaces are permanently deformed and will not reseal properly if the gasket is reused.
The condition of the surfaces on both the cylinder head and engine block are also critical because MLS gaskets are very unforgiving. To seal properly, the head and/or block must have a surface finish that meets certain specifications. Some MLS gaskets require very smooth finishes of 20 microinches or less. A traditional head gasket on a cast iron engine, by comparison, requires a surface finish of 60 to 120 microinches. For bimetal engines, the latest smoothness recommendations are a finish of 20 to 50 microinches.
Some aftermarket replacement gaskets for engines originally equipped with MLS gaskets resemble conventional head gaskets but have a special coating that allows the gasket to seal properly and accommodate a rougher finish of up to 60 microinches. At the same time, some gasket manufacturers have introduced MLS gaskets for problem engine applications that were not originally equipped with this type of head gasket.
Flatness is also important for a good seal. There should be no more than .002 inch out-of-flat sideways across any cylinder head or block surface, and no more than .003 inch out-of-flat lengthwise in a V6 head, .004 inch in a four cylinder or V8 head, or .006 inch in a straight six head. The head and/or block should be resurfaced if it is not within flatness specifications.
Other items that may be needed when replacing a head gasket include coolant, oil, filters, spark plugs and additional gaskets for the intake and exhaust manifolds and valve covers.
Distributorless Ignition Systems (DIS) and Coil-On-Plug (COP) ignition systems have eliminated the distributor cap and rotor on many engines today, but not the coil. The ignition coils in DIS and COP applications still perform the same basic function as the single coil used with a distributor ignition system. They all create the high voltage needed to fire the spark plugs (5,000 to 35,000 or more volts.) The only differences are in the design of the coils and the number used.
All coils are essentially transformers that consist of an iron core surrounded by primary and secondary windings. The primary windings are a much larger diameter wire than the secondary windings, but have fewer turns around the core. The ratio of turns between the primary and secondary windings determines the coils output potential (the higher the ratio, the higher the maximum output voltage). Most coils have about 10 times as many secondary windings as primary windings. High-performance coils have more.
Conventional canister or can-style coils used with older distributor-ignition systems usually have a common primary and secondary ground connection. High-energy coils may use a similar design or have isolated primary and secondary windings. DIS coils may have isolated primary and secondary windings (typical of the waste spark systems) or a common primary circuit with an isolated secondary circuit. COP coils usually have a common primary and secondary ground junction.
With all types of coils, the primary and secondary windings are insulated from one another and do not touch. The resistance of the primary winding is typically very low (less than a couple of ohms), while that of the secondary windings is high (segmented bobbin designs are usually in the 6,500 ohm range, while serial bobbin designs usually fall in the 10,000 to 14,000 ohm range).
Though coils are very reliable, they sometimes fail. Coils run hot because of the voltage that is constantly surging through them. Over time, the combination of heat and voltage may break down the insulation between the windings, coil housing or tower. If a coil problem is suspected, the coils primary and secondary resistance can be measured with an ohmmeter. If either is out of specification, the coil needs to be replaced.
A short- or lower-than-normal resistance in the primary windings allows excessive current to flow through the coil, which can quickly damage the ignition module. This may also reduce the coils voltage output resulting in a weak spark, hard starting and hesitation or misfire under load or when accelerating.
An open or high resistance in the coil primary windings will not usually damage the ignition module right away, but it may cause the module to run hot and shorten its life. With this condition, coil output will be low or non-existent (weak spark or no spark).
A short or low resistance in the coils secondary windings will result in a weak spark, but it will not damage the module.
An open or high resistance in the coils secondary windings will also cause a weak spark or no spark, and it may also damage the ignition module due to feedback induction through the primary circuit.
When a coil failure occurs on a distributor ignition system, it affects all of the cylinders. But with DIS and COP systems, a single coil failure will only affect one cylinder (or paired cylinders in the case of waste spark DIS systems). On 1996 and newer vehicles, the OBD II system should detect coil problems as well as misfires and generate a fault code that identifies the problem coil or cylinder.
Replacement coils must always be the same basic type as the original and have the same primary resistance as the original. Using the wrong coil may damage other ignition components or cause the new coil to fail.
If a customer is experiencing repeated coil failures, the coil may be working too hard. The underlying cause is usually high secondary resistance (bad spark plug wire or spark plugs) or in some cases a lean fuel condition (dirty injectors, vacuum leak or leaky EGR valve).
Future coil problems can often be avoided by cleaning the connectors and terminals when the coil is replaced. Corrosion can cause intermittent operation and loss of continuity, which may contribute to component failure. Applying dielectric grease to these connections can help prevent corrosion and assure a good connection.
On high-mileage engines with distributors or DIS ignition systems, you should also recommend replacing the spark plug wires to assure a good hot spark. New plugs should also be installed if the original conventional plugs are fouled or have more than 45,000 miles on them.
Oxygen sensors are at the top of the list of most important sensors on a vehicle today because of their effect on fuel economy, performance and emissions.Almost every vehicle thats been built since the mid-1970s has one or more O2 sensors, and many newer vehicles with V6 and V8 engines have as many as four.
Oxygen sensors are mounted in the exhaust manifold and behind the catalytic converter, but they are actually part of the fuel control system. Their job is to read the amount of unburned oxygen in the exhaust. This tells the computer two things: how "rich" or "lean" the fuel mixture is running, and whether or not the catalytic converter is doing its job and reducing pollutants in the exhaust.
Oxygen sensors generate a voltage that changes with the amount of unburned oxygen in the exhaust. When the fuel mixture is rich, there is little unburned oxygen left over and the sensors output goes up. When the fuel mixture is lean, there is lots of unburned oxygen and the sensors output drops. As the fuel mixture changes back and forth from rich to lean, the O2 sensors output switches back and forth in lockstep with the fuel mixture. This allows the powertrain control module (PCM) to monitor whats happening and rebalance the fuel mixture to keep emissions to a minimum.
"Upstream" O2 sensors (the ones mounted in the exhaust manifold) provide the feedback signal that the PCM uses to control the fuel mixture when the engine is warm and running in "closed loop."
"Downstream" O2 sensors (the ones mounted in or behind the converter) are used on 1996 and newer vehicles with OBD II. Their job is to help the PCM keep an eye on converter efficiency. Some vehicles also use the downstream O2 signal for long-term fuel trim adjustments.
A good upstream O2 sensor will produce a voltage signal that changes rapidly from minimum to maximum (typically 0.1 to 0.9 volts). A good downstream O2 sensor should show little switching activity if the converter is working efficiently. If the downstream O2 sensor starts switching like the upstream sensor, it means the converter isnt doing much. The OBD II will then turn on the Check Engine light and set a converter code.
As the O2 sensors age, they slow down. Other problems such as excessive oil burning or a coolant leak inside the engine (blown head gasket) may contaminate the O2 sensor and ruin it. If an O2 sensor isnt producing a good signal or isnt responding quickly enough to changes in the fuel mixture, it may prevent the fuel control system from going into closed loop and/or increase fuel consumption and emissions. Either way, the O2 sensor needs to be replaced.
The OBD II system also monitors the performance of all the O2 sensors and will flag a fault if it detects a problem. The vehicles owner may not notice anything wrong, but if the OBD II light is on and theres an O2 sensor code, it may indicate the need to replace the sensor. Further diagnosis is usually required to confirm the problem.
On older vehicles, replacing the oxygen sensors at specific mileage intervals was often recommended for preventive maintenance. The O2 sensors in many 1970s and 1980s vintage vehicles had recommended replacement intervals of 30,000 to 50,000 miles. On newer vehicles with OBD II, the O2 sensors are designed for a service life of 100,000 miles or more so there are no scheduled maintenance replacement intervals. Yet many experts recommend replacing high-mileage sensors to restore like-new performance. This is especially important on the older cars (those built prior to 1996) that dont have O2 sensors as durable as those on todays cars and trucks.
Replacement sensors must be the same basic type as the original (heated or unheated), have the same number of wires (one to four), and have the same performance characteristics and heater wattage requirements. Installing the wrong O2 sensor could affect engine performance and possibly damage the heater control circuit in the engine computer.When the old sensor is removed, it should be carefully inspected for signs of contamination. Some discoloration is normal, but heavy black deposits indicate an over-rich fuel mixture, dark brown deposits indicate high oil consumption, white or reddish deposits indicate harmful fuel additives, and light-colored or grainy deposits indicate a coolant leak. If the source of contamination isnt identified and fixed, the replacement sensor may suffer the same fate.
An O2 sensor that has never been removed may decide to take the threads in the exhaust manifold with it when it comes out. If this happens, your customer will also need a thread repair kit and/or tool to repair the threads in the manifold. Various types of thread inserts are available for this purpose.
Every engine requires a certain amount of oil flow to keep the bearings, camshaft, valvetrain and other moving parts lubricated.
This is provided by the oil pump. The oil pump doesnt actually create oil pressure. All the pump does is displace oil and push it into the oil galleys so it can flow to the bearings and upper valvetrain. What actually creates the oil pressure is the resistance the oil encounters as it circulates through the engine.
Most manufacturers recommend a minimum of 10 psi of oil pressure for every 1,000 rpm of engine speed. Using these numbers, most stock engines have about 50 to 60 psi of oil pressure. But some engines need more.
There are three basic types of oil pumps:
- Twin gear pumps, also called "external" pumps, use a pair of intermeshing gears to pump oil. One gear is driven by a shaft and the second gear is driven by the first gear. The pump is usually driven by a shaft that connects to the crankshaft, camshaft or distributor shaft. Thus, the pump operates at half engine rpm. The pump gears turn in opposite directions. This traps oil between the gear teeth and carries it around the outside of each gear from the pickup tube inlet to the pump outlet. The tight clearances between the gears prevents the oil from flowing backwards to the inlet.
- Rotor pumps, also called "gerotor" pumps, have an inner gear that turns inside an outer rotor. The inner gear has one less lobe than the outer rotor. The inner gear is also mounted slightly offcenter to the outer rotor, which forces the outer rotor to spin at about 80 percent of the speed of the inner gear. This creates a bellows-like pumping action that pulls oil from the inlet port and pushes it towards the outlet port. Close tolerances are required for good pumping efficiency. This type of pump may also be located in the crankcase.
- Front cover pumps, also called "internal/external" pumps are usually located in the front engine cover. This is also a rotor style pump with an inner drive gear and outer rotor, but the inner gear is mounted directly on the crankshaft. The direct drive approach eliminates the need for a separate pump drive shaft. This type of pump turns at the same rpm as the engine, so it generates more pressure at idle and does a better job of sucking oil from the crankcase and getting it to the upper valvetrain in a hurry. Thats why front cover pumps are used on many overhead cam engines. When this type of pump becomes worn, it is not always necessary to replace the entire cover assembly provided the pump housing inside the cover is not worn or damaged. A new drive gear can be mounted on the crankshaft, and a new rotor can be installed in the cover to rejuvenate the pump.
With all three types of pumps, wear and damage are major concerns. Wear that increases internal clearances between the gears, rotor and housing will reduce the amount of oil the pump displaces and cause a drop in oil pressure and delivery volume. Thats why high-mileage oil pumps may need to be replaced.
Low oil pressure indicates trouble and may be caused by a low oil level, worn main and rod bearings or a worn oil pump. Low oil pressure can lead to bearing seizure and engine failure, so it should not be ignored. Sometimes a bad oil pressure sending unit will give a false alarm. But if oil pressure is really low and the crankcase is full, the engine may need bearings and/or a new oil pump.
For some applications, you might recommend a "high-volume" or a "high-pressure" oil pump. High-volume pumps typically have longer gear sets to displace more oil. A high-volume oil pump may flow 20 to 25 percent more oil than a stock pump to increase oil pressure at idle and to compensate for increased bearing clearances and wear in a high-mileage engine. But a high-volume oil pump is no cure-all for worn bearings or sloppy bearing clearances. A high-pressure oil pump, by comparison, uses a stiffer relief valve that does not open until a higher pressure is reached (75 psi or higher). This type of pump can provide additional oil pressure at high rpm but wont have any effect on idle pressure when the pump is turning slowly.
Related products that may also be needed when replacing an oil pump include oil, a new filter and a pan gasket and/or front cover gasket set.
There have been quite a few changes in refrigerant over the last several years. Now that there's more than one type of refrigerant on the market,
it's important to know the challenges of selling this category.The cooling process starts when high-pressure liquid refrigerant enters the evaporator (the heat exchanger inside the HVAC unit in the passenger compartment.) A sudden drop in pressure causes the refrigerant to vaporize. This has a chilling effect on air flowing past the evaporator. The heat absorbed by the refrigerant vapor is then carried back to the compressor. The compressor pumps it to the condenser (the other heat exchanger mounted in front of the radiator) where air cools the vapor, carries away the excess heat and causes the vapor to change back into a liquid to complete its journey again.
Refrigerant is never used up. It circulates in a continuous loop as long as the A/C system remains leak-free. But after years of service, some seepage occurs through seals and hoses. Wear in the compressor shaft seal and corrosion inside the evaporator or condenser can also create leaks. As refrigerant is lost, cooling performance goes down. Eventually the system is unable to cool the vehicle adequately and service is required.
Recharging an A/C system that is low on refrigerant may be all that's need to restore cooling performance. But in most instances, the system will have leaks that need to be pinpointed and repaired before the system is recharged. Refrigerant leaks can be found by adding special dye to the system or by using an electronic leak detector. Some vehicle manufacturers now add leak-detection dye to the refrigerant charge in new vehicles to make leak detection easier. Most dyes are fluorescent and glow brightly under ultraviolet light.
Up until 1993, virtually all automotive A/C systems used R-12 (Freon) refrigerant. But scientists discovered that chlorine in R-12 and other man-made chlorofluorocarbon (CFCs) compounds were damaging the ozone layer high in the atmosphere that filters out most of the sun's harmful ultraviolet radiation. So in 1994, vehicle manufacturers began switching to a new "ozone-safe" refrigerant that contained no chlorine. The new refrigerant that been has used ever since is R-134a.)
The production of R-12 ended in 1996, and all vehicles built since 1996 in the U.S. have A/C systems charged with R-134a. Like R-12, R-134a is odorless, nontoxic and nonflammable under most conditions. It's cooling characteristics are similar to R-12, but it operates at slightly higher pressures.
Because of the high cost and scarcity of R-12, most older vehicles are converted to R-134a when major repairs (like replacing a compressor or condenser) are needed. Other alternative refrigerants are available, but using them increases the risk of accidental refrigerant cross-contamination.
By law, all refrigerants must be recovered and recycled when a vehicle is serviced. This applies to older vehicles with R-12 as well as newer vehicles with R-134a. Venting refrigerant into the atmosphere is not allowed.
If R-134a or some other chemical is used to recharge an older vehicle that still contains R-12, it will cross-contaminate the vehicle's A/C system and any recovery/recycling equipment that is later attached to service the vehicle. Cross-contamination is a serious issue because it can affect cooling performance and increase the risk of compressor failure. R-134a is not compatible with mineral-based compressor oil in older R-12 systems.
Retrofitting an older R-12 system requires removing as much of the old mineral oil as possible, recovering any residual R-12 that may still be in the system, recharging the system with R-134a and adding a compatible compressor lubricant. This would be POE oil or a specific viscosity of PAG specified by the compressor manufacturer. Compressor replacement may also be required if the original compressor has Viton seals (Viton is not compatible with R-134a). This applies to certain Audi, Honda, Infiniti and Nissan vehicles. Noncompatible seals and O-rings may also have to be replaced.
Federal law requires the permanent installation of R-134a fittings on the high and low service ports of a retrofitted system to reduce the chance of cross-contamination. Labels must also be installed that identify the system as being converted to R-134a.
Federal law also prohibits the use of flammable refrigerants in automotive A/C systems such as propane, butane or other hydrocarbons. Such chemicals could cause an explosion or fire where they leak into the passenger compartment. The only refrigerant approved by vehicle manufacturers for retrofits or late-model vehicles is R-134a.
When a customer needs a new tank-mounted electric fuel pump, youll usually need more information than the year, make and model of the vehicle to figure out which pump fits the application. The electric fuel pumps that are used in late-model vehicles can vary according to the engine, drivetrain and even the size of the fuel tank. On some pickup trucks and sports utility vehicles, four-wheel drive versions use one pump, and two-wheel drive versions use a different pump. A pickup truck equipped with twin tanks or an oversize tank may require a different pump than an identical truck with a standard-sized fuel tank. Its crazy, but thats the way vehicles are built today.
To find the correct replacement pump for some vehicles, youll probably need the VIN number too. The type of pump used can even vary according to the build date.
What happens if you give your customer the wrong pump? If the pump is too long, it may touch the bottom of the tank causing an objectionable noise. A pump that is too short may run out of fuel even though theres still fuel in the tank. A pump with the wrong pressure can cause all kinds of starting, driveability and emissions problems. So correctly identifying the application is extremely important.
You should also quiz your customer to verify he has correctly diagnosed the problem. In other words, is the pump really bad, or is something else causing a fuel delivery problem?
An electric fuel pump wont pump if it doesnt get the proper voltage. A dead pump can be caused by a bad relay, a loose or corroded wiring connector or an inertia safety switch that has been tripped (this opens the pump circuit to minimize the risk of a fire in an accident.)
Low voltage in the pumps power supply circuit or high resistance in the pumps ground connection can prevent a pump from spinning at normal speed causing a drop in fuel delivery and pressure that starves the engine for fuel.
Mechanical problems such as a kinked fuel line, a bad fuel pressure regulator, a plugged fuel filter or a clogged fuel inlet strainer can also restrict fuel delivery and cause performance problems too.
If the fuel pump is receiving normal voltage, has a good ground connection and the lines are unobstructed, but it fails to run or cant deliver normal fuel pressure or volume, it needs to be replaced.
Most OEM pumps are built to last 100,000 miles or more, but many never make it that far for a variety of reasons. One is contaminants such as rust and sediment inside the fuel tank. As a vehicle ages, the inside of the fuel tank often becomes coated with rust as the protective plating wears away and moisture condensation attacks the steel. The particles of rust flake off and are sucked into the pump. Dirt and sediment that finds its way into the tank during refueling can also add to the problem by accelerating pump wear.
Tank-mounted electric fuel pumps also use the fuel as a lubricant and as a coolant. If the tank runs low and the pump sucks in air, this may cause additional damage.
Customers should be advised to clean and inspect the inside of the fuel tank when replacing a fuel pump in a high-mileage vehicle. If the tank is dirty, it should be drained and cleaned. If it is full of rust, the tank should be replaced to prevent a repeat pump failure and fuel leaks.
Replacement options include replacing just the fuel pump itself or replacing the entire fuel pump and sending unit assembly. The complete modular assemblies are more expensive than a pump by itself but are easier to install. If the original hanger brackets are rusty, the whole assembly should probably be replaced to prevent additional problems down the road. On many late-model imports, the pump cannot be replaced separately. A modular unit is all thats available.
Regardless of whether the pump itself or the whole pump assembly is replaced, a new strainer should always be installed on the pump pickup. The strainer is the pumps first line of protection against any debris that might get into the fuel tank. You should also recommend a new fuel filter to protect the rest of the fuel system.
Other items that may be needed include fuel hose if the original hose is cracked, leaking or damaged and hose clamps or fittings. For customers who drive older vehicles with mechanical fuel pumps that may no longer be available, finding a replacement pump can be a challenge. One alternative is an aftermarket in-line electric pump. Universal pumps are easy to install (just find a convenient location in the fuel line and splice it in) and typically provide better fuel delivery. They run cooler, too, and can eliminate "vapor lock" problems during hot summer weather.
The thermostat is a temperature-regulating device in the engine's cooling system. It is usually located where the upper radiator hose connects to the engine block, but it may be located elsewhere on some engines. The thermostat blocks the flow of coolant between the engine and radiator to speed engine warm up after a cold start. It also regulates the flow of coolant once the engine is hot so that the engine maintains a more or less consistent operating temperature. It does this by opening and closing to vary the coolant flow.
Inside the thermostat is a wax-filled element that expands as the coolant warms up. Eventually it pushes the spring-loaded valve open so coolant can pass. As the coolant begins to cool down, the spring pushes the valve shut as the wax-filled element contracts. The cycle then repeats to keep the coolant within a certain preset temperature range while the vehicle is being driven.
A quick warm-up is necessary for several reasons. One is to improve cold driveability and emissions. Engines don't run well when they are cold because fuel is slow to vaporize. This requires a richer fuel mixture, which increases fuel consumption and emissions. As the engine warms up, the fuel mixture can be made leaner. Once the coolant reaches a certain temperature, the computer goes into a "closed-loop" mode of operation and begins to vary the fuel mixture for best performance, economy and emissions.
A quick warm-up and a consistent operating temperature of 190 to 215 degrees also reduces blowby. When a cold engine is first started, there is more clearance between the pistons, rings and cylinders. Blowby from the combustion chambers pushes moisture and unburned fuel into the crankcase where it dilutes the oil. Fuel also washes oil off of the cylinder walls, which accelerates wear. As the engine warms up, the parts expand to reduce clearances and blowby.
An engine should never be run without a functioning thermostat in place because doing so can cause a variety of problems. The engine will be slow to warm up and suffer increased blowby and cylinder wear as a result. The coolant may also never get hot enough for the computer to go into closed loop. This will make the fuel mixture run rich and increase fuel consumption and emissions.
A thermostat can fail one of two ways. They can stick shut, block the flow of coolant and make the engine overheat; or, they can remain open or not fully close and prevent the engine from reaching normal operating temperature. This will reduce heater output, prevent the computer from going into closed loop and increase blowby and wear. Either way, a bad thermostat must be replaced.
Overheating doesn't always mean the engine has a stuck thermostat. Other causes include low coolant, leaks, a defective cooling fan, an obstructed or plugged radiator, a bad water pump or even a plugged exhaust.
If an engine has overheated because of another problem, the thermostat should also be replaced when repairs are made because high temperatures can damage the thermostat's sensing element.
A replacement thermostat should have the same temperature rating as the OE thermostat. The rating is usually marked on the thermostat. Most vehicles require a 192- to 195-degree thermostat. But you can't always go by the rating on the old thermostat because it may have been replaced before with one that was different from the original. Go by what the book recommends.
Installing a hotter thermostat can improve heater output during cold weather, but it may also increase the risk of overheating during hot summer weather. A cooler thermostat may reduce the risk of overheating in the summer, but it may delay or interfere with the computer going into closed loop. That's why the stock temperature is usually the best choice.
When a thermostat is replaced, the housing and mating surface on the engine must be cleaned so that a new gasket can be installed. The housing should be replaced if it is badly corroded or leaks. The thermostat must be installed with the temperature sensing element toward the engine. If installed upside down, the thermostat won't open when the engine gets hot.
Other items your customer may need when changing a thermostat include antifreeze, belts and hoses. The radiator cap should also be checked to make sure it has the correct pressure rating for the application and is not damaged or leaking. Equally important is getting all of the air out of the cooling system when it is refilled. Some vehicles may have one or more air bleeds at various points in the cooling system to vent air. Thermostats with a "jiggle pin" make it easier for air to escape when the cooling system is being filled. Air pockets may prevent the thermostat from opening and/or cause the engine to overheat.
Many overhead cam engines use timing belts rather than chains to drive their camshafts. Belts are quieter than chains, less expensive and less prone to harmonic vibrations. Timing belts are made of synthetic rubber (neoprene) reinforced with tough fiber cords. But contrary to what you might think, timing belts do not stretch with accumulated mileage and wear. The reinforcing fibers make them virtually unstretchable but they do wear out.
The combination of constant bending and flexing, combined with heat and tension, fatigues the reinforcing strands and hardens the rubber. This leads to cracking, fraying and ultimately failure. Therefore, belts must be replaced at certain mileage intervals to minimize the risk of breakage.
For many overhead cam (OHC) engines, the OEM recommended timing belt replacement interval is every 60,000 miles. But for some, the replacement interval may be at a higher or lower mileage. On some engines, it may be every 40,000 miles or as much as 100,000 miles on others.
A broken timing belt can cause serious engine damage in an "interference" engine that does not have enough internal clearance to prevent the valves from hitting the pistons if the belt fails.
Always refer to the vehicle manufacturer's belt replacement recommendations, which can be found in the vehicle owners manual or your timing belt catalog or electronic database.
An OHC timing belt should also be replaced regardless of mileage if it has frayed or exposed cords, damaged teeth, hunks of rubber missing, deep cracks, excessive surface cracking or severe glazing. Small surface cracks on the ribbing are normal. But extensive cracking or deep cracks aren't.
A new timing belt may also be needed if the cylinder head has to come off of the engine for other repairs, or if a timing belt-driven water pump is being replaced. In both cases, the belt has to come off anyway so there is no extra labor required to replace it. Replacing it now can save the customer extra labor costs later on.
Many timing belt failures are actually caused by faulty belt tensioners and pulleys. Like the belts, these components have a limited service life and wear out with increased mileage. Tensioner bearings are "sealed for life" and aren't serviceable, so there's no way to clean, inspect or re-lubricate the bearings when a timing belt is changed. On many newer engines, spring-loaded automatic tensioners are used to keep the timing belt tight. If the slide plate is worn or sticking, or the spring is weak, it can prevent the tensioner from maintaining proper pressure. It's difficult to determine the true condition of the tensioner components when they're not running under a load. Consequently, a simple visual inspection may miss tensioner bearings that are on the verge of failure.
Replacing the tensioner components along with the belt will restore the timing belt drive to like-new condition and significantly reduce the risk of future problems. So always recommend a complete timing kit that includes a new tensioner and idler pulley along with the belt. Many technicians don't replace these components when changing a belt, then wonder why the new belt they installed failed a few thousand miles later. Timing kits are available for most applications and reduce the chance of mismatched parts when replacing timing components. Timing belts can have one of several different teeth profiles in addition to different lengths and widths. If there's a mismatch between the belt and drive sprockets, tensioner or idler pulleys, it will ruin the belt. Replacement belts must be the same as the original. The length, width and tooth profile of the new and the old should all match.
It's also important to clean and inspect the camshaft and crankshaft drive sprockets when changing a timing belt. If either sprocket shows unusual wear or damage, these components should also be replaced to protect the new belt.
Other components that should be carefully inspected when changing a belt include the motor mounts, water pump and crankshaft and camshaft front oil seals. Oil leaks can contaminate a belt and shorten its service life. Any oil leaks in the vicinity of the timing belt should be repaired before the new belt is installed.
The bottom ends on most import engines today are nearly bullet-proof, but problems still occur. Most import engines can go 150,000 miles or more with regular oil and filter changes. But if the vehicles owner scrimps on maintenance, forgets to have the oil and filter changed at the recommended intervals or uses a cheap grade of oil, the engine wont last.
The first sign of trouble may be lower-than-normal oil pressure readings or an oil warning lamp. The engine may start to use oil, or misfire may occur because of oil-fouled spark plugs. A compression check may reveal low compression in most cylinders due to ring and bore wear. Or, the engine may simply seize up and call it quits because of a spun rod or main bearing.
By the time an engine needs rings or bearings, it usually needs a complete overhaul. Thats why complete engine kits are such a popular product today. Labor is such a huge part of almost any kind of internal engine repair that it makes more sense to overhaul the entire engine rather than to fix individual items.
If an engine is seized up and wont crank, the rod bearing often does enough damage to the crank journal that the crank will have to be reground or replaced. A spun main bearing can do the same thing as well as chew up the bearing bore in the block. This usually requires the crank bores to be align honed.
All bearings will show some degree of wear, some scoring or wiping, pitting, flaking or dirt embedded in the surface. But when one or more crankshaft bearings are found to be damaged or show unusual or uneven wear, it typically indicates other problems that need correcting. The straightness of the crankshaft and main bore alignment need to be carefully checked along with the condition, shape and dimensions of the crankshaft journals.
The diameter of the crankshaft journals should be within .001 in. of its original size, or within .001 in. of standard regrind dimensions for proper oil clearances with a replacement bearing. If a journal has been previously reground, theres usually a machinists mark stamped by the journal. A 10, 20 or 30 would indicate the crank has already been ground to undersize.
Replacement bearings for import engines are available in various materials and designs. Most late-model engines have aluminum main and rod bearings as original equipment. OEMs like aluminum bearings because they provide long-lasting durability, high-temperature resistance and contain no lead (an environmental pollutant). Aluminum bearings do not have as much embedability as bimetal or trimetal bearings, but makers of the aluminum bearings say this is actually an advantage because the bearings flush out debris rather than trap it. Some aluminum bearings have a thicker layer of alloy to provide increased embedability and conformability.
Trimetal bearings are still popular as replacement bearings in the aftermarket because they tend to be more forgiving. A typical trimetal bearing has a steel backing plate covered with a layer of copper/lead overlayed with a thin coating of babbit. This provides a good combination of strength, surface action, conformability and embedability say the makers of such bearings.
Like bearings, piston rings also wear out as the miles add up. Many Japanese engines have steel-top compression rings to better withstand higher operating temperatures and detonation. Many of these rings also have a hard nitride coating to improve wear resistance. Even so, they dont last forever.
Before new rings can be installed, the cylinder bores must be reconditioned to restore the proper cross-hatch and surface finish. If the cylinders are worn (too much taper), the engine will have to be bored to accept oversize pistons and rings.Piston slap is a classic symptom of too much clearance between the pistons and cylinder bores. Piston slap is most audible when a cold engine because clearances are greatest. Pistons can also scuff if the engine overheats, burn through if the engine is experiencing preignition or detonation, or crack or break from detonation or high temperatures. Any underlying problems that contribute to overheating, detonation or preignition must be identified and eliminated.
Another reason why a customer may want to replace pistons would be to change the stock compression ratio: up for more power on gasoline, or down to control detonation if the engine is being turbocharged or supercharged.
The heart of the cooling system is the water pump. Water pumps move hundreds of gallons of coolant per hour, mile after mile. The pump shaft and bearings are under constant load not only from the drive belt or timing belt but also from the fan on vehicles with pump-mounted mechanical cooling fans. Eventually the water pump bearings and seal wear out, and the pump begins to leak. The pump must then be replaced to prevent loss of coolant and engine overheating. A pump must also be replaced if the shaft shows any visible wobble or the bearings are making noise.
If a vehicle has a pump-mounted mechanical fan with a fan clutch, recommend a new fan clutch, too. The service life of the fan clutch is about the same as the pump. A slipping fan clutch will reduce radiator cooling and may cause the engine to overheat.Most OE water pumps last 60,000 miles or more. But a water pump can fail prematurely as a result of coolant contamination and cooling system corrosion. If the coolant is not maintained and replaced periodically, the corrosion-inhibitors eventually break down. Once this happens, rust and scale begin to attack the pump and everything else in the cooling system. When a new water pump is first installed, some seepage from the weep hole is normal. It takes a few hours of operation for the seal to properly seat itself. However, any weeping after this break-in period means the seal is damaged. A failed seal allows coolant to leak through the bearings and wash away the lubricant.
Many pumps have ceramic seals, that are wear resistant and provide long service life but they can be cracked if the engine is started without coolant in the system, or if someone adds cold coolant to a hot engine.
Sometimes a water pump shaft will break. A clean fracture through the front bearing race part of the shaft means the pump was subjected to a sudden overload or imbalance caused by vibration. Rapid engine acceleration may have contributed to this kind of failure, too. If a broken shaft is discolored (usually blue), the damage was gradual indicating excessive heat build-up from imbalance or overloading. An imbalanced or bent fan, loose fan clutch, bent pump pulley or excessive drive belt tension can all be contributing factors.
Several things should always be done when replacing a water pump to protect it against possible damage. One is to thoroughly clean and flush the cooling system to remove contaminants. The cooling system and radiator cap should also be inspected and pressure tested to check for leaks. The system can then be refilled with a 50/50 mixture of distilled water and the type of antifreeze recommended by the vehicle manufacturer.
The condition and alignment of the pump drive pulley should also be checked to make sure it is parallel and true to the other pulleys.
As for the pump itself, make sure your customer gets the correct one for the engine. Standard and reverse rotation pumps may look the same on the outside but are not interchangeable because of the direction of the impeller inside. A standard rotation pump will be driven by the front side of the belt, while a reverse rotation pump will be driven by the back of the belt.
For clear visibility and driving safety, wiper blades should be replaced at the first sign of trouble. Streaking, chattering and noisy operation are all clues that the wipers have reached the end of the road. But many people wait until they can barely see where they're going before they consider buying a new set of blades. It's false economy and a very bad idea, especially when the weather takes a turn for the worse and the wipers are needed to clear the glass.
Rain, sleet, snow, road splash and even bug splatter can all obscure the driver's vision of the road ahead and increase the risk of hitting something. How many accidents have been blamed on poor visibility during bad weather? Too many.
Wiper blades need to be replaced periodically because they don't last forever. Dirt and debris on the windshield wear away the wiping edge of the blades during normal use. Sunlight and ozone also age rubber blades and causes them to harden and lose their natural elasticity. This reduces their ability to wipe cleanly and quietly, and eventually it causes the rubber to split and crack.
A wiper blade must be flexible to provide the proper "squeegee"effect as it slides across the glass. If the rubber is stiff due to old age or extremely cold temperatures, it will skip and chatter leaving areas unwiped or smeared. The wiping edge of the blade must also be perfectly smooth and flat. If pitted, torn or ragged, the blade won't maintain full contact across the length of the blade, and it will streak the glass. Old blades can also develop a permanent set (called "parked"rubber) or curvature which prevents full contact with the windshield.
For all of these reasons, you should tell your customers to replace their wiper blades at least once a year to maintain good wiping performance, visibility and driving safety. Premium replacement blade holders typically have six to eight claws to spread the pressure of the wiper arm over a broader area of the blade. More claws also provides increased flexibility so the blade can more easily follow the curvature of a large, sloping windshield for full side-to-side contact.
Some replacement blades also offer better aerodynamics and include features such as slots and airfoils that help prevent windlift at higher speeds. This is especially important on vehicles with steeply sloping glass.
If they need new blades, recommend upgrading to a premium type of replacement blade. Premium blades are typically constructed with better materials for improved durability and visibility. Some use synthetic materials such as Teflon to provide a smoother wipe. Teflon reduces friction and is now used in many OE wipers on luxury vehicles and SUVs including Lincoln LS, Ford Navigator, Expedition and Explorer.New blades may be needed for the backglass or tailgate on a minivan, SUV, station wagon or hatchback car. Back wiper blades are often more neglected than the ones up front because they're used less often. But they're no less important than the front blades.Other items that may be needed include replacement wiper arms especially rear arms on minivans that are easily damaged in car washes.
Wipers can't do their job effectively if the windshield washer reservior is empty or isn't working. So make sure your customer doesn't forget a jug of windshield washer premix. If the washers are broken, he may need a new washer pump, pump reservoir or washer hoses. These parts are all part of the washer system and must be in good working condition for the wipers to do their job.When helping a customer choose a set of replacement blades or refills for his vehicle, make sure the new blades or refills are the same length as the original blades.Most wiper blades are simple to replace. The blade holder is usually attached to the wiper arm one of three ways: by a side pin (GM), by a bayonet clip (Ford and Chrysler) or by a hook (imports). The installation instructions that come with new blades usually show how the blades are mounted and how to replace them. Some replacement blades have the same type of OEM mounting configuration while others require the use of a small plastic adapter clip to attach the blade holder to the arm.
One way to prompt a potential sale is to ask customers when they last changed their blades. If they can't remember, or it has been more than a year, recommend a new set of blades or refills.With blade refills, there is usually a squeeze clip at one end of the blade that must be released to slide the old rubber out of the holder. But there are different width refills, so make sure your customer gets the right ones for his blade holders.