What is a valve cover gasket?
A standard internal combustion engine is made up of numerous components, all fitting together to function smoothly. However, these components must be sealed together to prevent loss of fluid while the engine is running.
This seal is created using special gaskets that are cut or formed to the exact dimensions required for correct installation. In the past, this type of seal was made from compressed fiber or cork of various thicknesses. Today, the majority of automotive seals are made from rubber-coated plastic or special fiberglass compounds.
One particular structural connection that requires the use of a gasket is the connection between an engine’s cylinder head and the valve cover gasket. A standard in-line engine has one cylinder head, while a V-configuration engine has two.
These heads contain the engine’s valvetrain components (valves, valve springs, and rocker arms) that work continuously to control the distribution of intake air to each cylinder and the delivery of burned gases to the exhaust. These valvetrain components are cooled and lubricated by a steady supply of engine oil.
Each cylinder head is closed by a valve cover. Valve covers were also called rocker arm covers in earlier maintenance literature. An engine’s valve cover prevents oil from leaking out of the cylinder head to which it is attached and prevents dirt from building up inside.
Between each cylinder head and valve cover is a valve cover gasket, which provides a much more efficient seal than a metal-to-metal connection. Without a valve cover gasket, oil would easily leak out of the connection between these two vital components.
Valve Cover Gasket Materials
Every valve cover gasket has a job to do (maintain a good seal and prevent oil leakage), but how well it does it depends on its design. Here are some common materials used for these gaskets:
Plastic
Plastic valve cover gaskets are becoming increasingly popular, especially on newer vehicles. They are lightweight, relatively durable, and heat resistant. However, for older engines, plastic seals may not be the best choice as they cannot withstand extreme or high temperatures.
Rubber
Rubber seals, especially those made with silicone or nitrile rubber, are heat resistant, durable, and durable. They withstand temperature changes well and hold their shape, eliminating the possibility of leaks. However, rubber and silicone seals tend to be more expensive than other seals.
Cork
Cork is the traditional choice for valve cover gaskets due to its low cost and ease of installation. It provides an adequate seal for most engines, but is not as durable as rubber or plastic seals.
Cork gaskets tend to compress over time, so they need to be replaced more frequently, and high temperatures can cause problems. Metallic gaskets are often made from aluminum or steel and are very durable, providing a reliable seal even in high-temperature environments. However, metal gaskets can be expensive and difficult to install compared to other materials.