A century ago, engines were supposed to leak, drip and smoke. It was normal, and no one thought anything about it. Today, however, things have changed considerably. Engines that leak, drip and smoke aren’t long for this world and certainly won’t pass an emissions test. Gaskets that leak have failed already or are about to lose the battle soon.
Modern gaskets are engineered for a specific application and should perform trouble-free AND leak-free without much more than routine maintenance. When a gasket does fail, it could be due to a variety of reasons, such as cooling-system neglect, oil contamination/dilution or inadequate surface preparation.
Today, there are better, more environmentally friendly materials and gasket designs to deal with fluids and vapors. High-tech elastomers and laser-welded seals, along with laser-cut carriers and multi-layer steel, are commonly used in modern vehicles. Using the right materials – and ensuring proper surface preparation and clamp load – makes the best seal.
When a seal fails, such as on a head gasket or intake manifold gasket, it may be due to coolant contaminating the oil. In some cases, the gasket materials are not compatible with the chemical compounds used in certain coolants. Plastic materials can degrade over time when exposed to OAT-type coolants. There are some manufacturers that make a solution to this issue using a stainless-steel carrier and molded rubber compound that’s compatible with a wide range of chemicals.
Poor surface preparation or warped heads can lead to leak paths. If left unaddressed, the condition can end up causing engine damage. Many motorists aren’t aware their engines are leaking small amounts of oil or coolant until it’s too late.
Removal and installation must be carefully performed so as not to damage the surface for the gasket. Grinding or gauging soft aluminum with the wrong tool or leaving gasket material can be a recipe for a failure. But more common is using the wrong type of coolant or using carburetor cleaner that leaves a non-dry surface. Sealing products depend on friction, which is why it’s better to use brake clean or contact cleaner. These products provide a clean and dry surface for the gasket to seal.
The trend in gasket design is an ongoing shift away from soft material or compound gaskets to metal or elastomer solutions. Gasket materials are continually evolving to address heat resistance, tensile strength, conformability and more. Most improvements come from understanding how all the components work together, which has increased the reliability of the engines. Today’s thinking is to allow some joints to move slightly instead of sticking together.
For customers installing replacement head gaskets, they’ll need a clean and smooth surface, and they shouldn’t use RTV. Silicone sealant is not recommended to install new MLS-style gaskets. The gaskets should be installed dry. There are some gaskets where a spot of RTV is required to help seal corners and to help keep the gasket in place, such as on timing covers, valve covers and some intake and exhaust manifolds, but refer to manufacturer instructions to be sure.
You can help your customer – and your sales – by recommending the right gaskets for the job. Selling gaskets in sets is an excellent way to cover the bases. Water pumps often are replaced along with timing belts or chains, so making sure your customer has the right timing-cover gaskets and a good-quality water-pump gasket will make their job easy – and you a hero.