What Is A Valve Cover Gasket?

As a vehicle's engine operates, the intake and exhaust valves open and close rapidly while the pistons move up and down in the cylinder. These mechanical actions require a constant supply of hot oil to lubricate the moving parts. The valve cover gasket helps to prevent oil from escaping the engine by providing a tight seal between the engine and valve cover, typically made of rubber, plastic, or cork. As a result, the valve cover gasket is one of the engine's critical components.

However, like other engine components, the valve cover gasket will wear out over time and may no longer be able to contain the engine oil effectively. A worn or leaking valve cover gasket can cause oil to escape and allow debris and small particles to enter the space between the pistons and cylinder, resulting in friction and increased wear and tear. The escaping oil also means that the engine components will receive less lubrication and may begin to grind against each other, putting more stress on the engine and shortening its lifespan. It is important to be aware of the signs of a leaking valve cover gasket and to have it replaced promptly.

Signs Of A Leaking Valve Cover Gasket

If the valve cover gasket is leaking, there are multiple tell-tale signs that indicate that. They go as follows:

• Low engine oil. The engine may start to run low on oil, causing friction and increased engine temperature, which can ultimately lead to engine failure or fire. If the check engine light illuminates, it is important to check the valve cover gasket promptly.
• Rough-running engine and misfires. The engine may not run smoothly due to insufficient lubrication, and oil leaks can reach the spark plugs, causing misfires and performance issues. In some cases, ignition of engine oil may also cause the vehicle to catch fire.
• Burning oil smell. Oil leaks can reach the fuel intake, cylinder head, or other hot engine parts, causing a burning oil smell inside the vehicle and excessive smoke from the exhaust when the vehicle is running.
• Dirty or oily valve cover. A dirty or oily valve cover is another strong indication of a faulty or leaking cover gasket. Oil leaks can absorb dirt and debris under the hood, which hardens on the valve cover or cylinder head. It is important to check the condition of the valve cover gasket during an oil change or any time the valve cover looks dirty when inspecting the vehicle's engine.

How To Replace A Valve Cover Gasket

Replacing the gasket involves the following steps: 

• Tighten the Valve Cover. The valve cover gaskets may loosen due to engine vibrations, but tightening the valve cover with a torque wrench should stop the leak. However, over-tightening the bolts will not prevent a worn-out gasket from leaking. It is crucial to monitor oil levels after tightening the valve cover. If there are still leaks, then the gasket needs to be replaced.
• Allow the Engine to Cool. Always allow the engine to cool down before trying to access the valve cover and consult the owner's manual on how to remove it. You may need to remove some plumbing or parts, including PVC hoses, throttle cables, spark plug tubes, and brackets, to access the valve cover.
• Remove the Valve Cover. Remove the valve cover bolts and take out the cover. If it is difficult to remove, tap it gently with a rubber mallet to loosen it. Cover the engine so that nothing falls inside it, as this could cause additional work.
• Remove and Replace the Old Gasket. Use your hand or a plastic material to remove the old gasket. Do not use a metal object, as it can create grooves or nicks that can cause leaks.
• Apply Silicone (if required). Only apply silicone or sealant if it is recommended, which is usually indicated in the service manual or the gasket instructions. Before applying, make sure all surfaces are cleaned and allow the silicone to cure before starting the engine.
• Reinstall the Valve Cover. Reinstall the valve cover with the new gasket in place and tighten the bolts to the recommended torque. Over-tightening the bolts can crack or deform the cover. Reinstall the plumbing and all the parts that were removed to access the valve cover.

Summary

The valve cover gasket is placed between the engine and the valve cover to keep the oil inside the engine body. A worn-out gasket can allow oil to leak into other parts of the engine, causing performance issues. Replacing the gasket is relatively inexpensive and a straightforward process, but it is always best to have a professional mechanic handle the job if you are unfamiliar with engine-related tasks.

Related Resources

• Research a Vehicle
• All Cars for Sale
• Sell My Car
• Compare Cars
• Car Finder Tool
• Car Ratings
• Shopping Guides
• New Car Previews
• Expert Car Reviews