Replacing Catalytic Converters

Replacing Catalytic Converters

When replacing a catalytic converter, it’s important to know whether the vehicle falls under EPA or CARB emissions standards.

Welcome readers, my name is Charles Dumont. Just for a little background on myself: I’ve been in the automotive aftermarket for around 40 years. I hold 13 ASE certifications. For many years, I was an automotive technician in California, where the the California Air Resources Board (CARB) has established strict emissions requirements that have been adopted by a number of other states. For most of my time in California, I was a certified smog-check technician. 

That all leads to the topic at hand: replacing catalytic converters. While catalytic converters and mufflers are similar in appearance, and they’re located in close proximity to each other underneath the vehicle, the process of selecting and replacing a catalytic converter is quite different from a muffler.

Mufflers are pretty straightforward. Over time, they deteriorate from vibration and the heat generated by the exhaust gasses. Eventually, they develop holes in the outside casing and leak exhaust gasses into the vehicle and make noise. In some states, drivers can be cited for loud exhaust noise. A quick trip to the auto parts store or the muffler shop will take care of that. 

The two basic types of mufflers are bolt-on and weld-on. If it’s a weld-on, the trip to the muffler shop is the easy way to go. A thorough inspection of the entire exhaust system also is highly recommended.

Catalytic converters are subject to the same exhaust gasses as a muffler. However, they also are sensitive to the overall condition of the engine, fuel system and ignition system. If the engine is burning oil or running too rich or lean, that will poison the converter and cause the “Check Engine” light to come on and set a P0420 code. When that happens, a thorough inspection of the engine and related components should be conducted. Simply replacing the catalytic converter is a short-lived repair. Also, the oxygen sensors should be replaced as a maintenance item at the same time.

A new aftermarket catalytic converter can be installed only if the original is missing, fails a state or local emissions inspection program or is plugged, leaking or has sustained physical damage. Most vehicles require catalytic-converter replacements when an illuminated “Check Engine” light indicates a converter failure or if the engine itself has failed an exhaust emissions test. To pass an exhaust emissions test, the converter must meet the exact configuration and capacity as specified by the OEM.

When replacing a catalytic converter or other emissions-control parts, it’s important to know whether the customer’s vehicle falls under EPA or CARB emissions standards. Some states follow California’s air-quality standards and some do not. The other states that follow the California guidelines are considered “CARB-compliant.”

The proper way to determine whether or not a vehicle falls under EPA or CARB guidelines is to look at the “Vehicle Emission Control Information” sticker in the engine compartment. (You could have your customer take a picture of the sticker and send it to you.) If the label references California, CARB or “50-State,” the vehicle falls under California’s emissions guidelines and will require a CARB-compliant catalytic converter.

Hope you enjoyed this column and I hope to bring you more information in the future.

You May Also Like

Understanding the Emission-Control System

These components should be high on the list of parts you sell.

Once hated and touted as “power robbers,” we’ve learned over the years how emission-control systems not only protect our environment, but also how they contribute to the overall performance, economy and longevity of today’s engines as an integral part of the combustion process.

Emission-control components are high on the list of parts you sell, because they affect vehicle operation, and if they’re not working properly, they result in the dreaded “Check Engine” light. There are many ways that the various emission systems on a vehicle tie together, but a look at the main players can help you develop a base understanding of how the overall system works.

Bleeding the Brakes

It’s a simple concept, but not without the occasional headache.

The ‘Other’ Gaskets

Why should head gaskets get all the glory?

Why Private Equity Loves the Automotive Aftermarket

The same qualities that make the aftermarket a great place to do business make it a compelling investment for PE.

How to Change a Headlight Bulb

There’s always an opportunity to help your DIY customers do the job right.

Other Posts

Hydraulic Suspension Bushings

They can isolate noise, vibration and harshness from entering the vehicle cabin more effectively than standard bushings.

A Closer Look at Lincoln-Mercury

The Mercury brand was shuttered in 2010, while Lincoln is enjoying a bit of a renaissance.

Bill Hanvey: Now’s the Time to Support Right to Repair

Hanvey details how “you and your company can take part in the most important battle our industry has ever faced.”

Selling Tie Rods and Steering Components

On a vehicle with rack-and-pinion steering, it’s not uncommon to replace outer tie-rod ends multiple times.