A Quick Guide to Valve Cover Gaskets

March 20, 2025

6 min read

March 20, 2025

6 min read

If your car's valve cover gasket brakes down, your engine can develop an oil leak. A leaky gasket disrupts the vacuum of the engine, causing it to run poorly.

Check out our step-by-step video and article about how to replace a valve cover gasket - opens in new window or tab. . And see our valve cover gasket buying guide - opens in new window or tab. .

What a Valve Cover Gasket Does

A mechanic wearing a black nitrile glove installs a fresh blue rubber gasket on a valve cover. — The valve cover gasket seals the engine’s “roof” to the cylinder head.

A modern engine is like a two-story house with a basement:

The first floor is the engine block , or “bottom end.” This is the main part of the engine where your pistons fire up and down.
The cylinder head , or “top end,” is on the second floor. This is where you’ll find valves and spark plugs and either your overhead camshafts or rocker arms.
The crankcase and oil pan are in the basement. This is the bottom side of the crankshaft, which turns the up and down motion of the pistons into the turning motion that drives your car.
Think of the valve cover as your roof. This is what sits on top of the cylinder head.

Gaskets seal every floor. There are gaskets at the oil pan, the crankcase, and between the cylinder block and the cylinder head. That’s your head gasket.

The valve cover gasket seals between the cylinder head and the valve cover. It’s a common source for leaks but the easiest gasket to replace.

A lot of oil runs through the cylinder head. The valve cover gasket provides a tight seal between the head and the valve cover, preventing leaks. Over time, it can deteriorate due to heat and pressure. When this happens, it needs to be replaced to stop oil leaks and damage to the engine.

Don’t overtighten a bad gasket. Valve cover gaskets are made of rubber, silicone, composite materials, or cork. Overtightening the valve cover bolts can put too much pressure on the gasket and make leaks worse.

Did your engine overheat? High temperatures can break down the compounds in the gasket, causing deterioration. It can leak oil and let contaminants into your engine.

When to Replace a Valve Cover Gasket

A vintage inline engine with a leaky valve cover gasket. — The coating of dusty oil below the valve cover gasket on this inline engine suggests that it's been leaking for a long time.

You can expect a valve cover gasket to last between 20,000 and 50,000 miles. However, some circumstances can cause a premature breakdown. Excess heat, in particular, is a common cause of bad gaskets, breaking down the material and causing leaks. Back pressure in the engine due to poor exhaust flow can also blow a leak in the gasket.

Small leaks lead to big leaks. If you know how to spot early signs of failure, you can replace the gasket before a serious leak occurs.

How do you know if your valve cover gasket is leaking?

The most noticeable symptom of a leaking valve cover gasket is a burning oil smell - opens in new window or tab. when your vehicle gets up to temperature. Any breach in the gasket allows oil to spill out into the engine compartment, causing the smell. It will be different from the smell of burning coolant from a bad head gasket.

You can also do a visual inspection to spot leaks. After your car is warmed up, check if oil is leaking onto other engine components or the ground under the car. Leaking oil will look and smell different from leaking coolant or from water dripping when your car’s air conditioning is running.

Oil can leak through a bad valve cover gasket onto the spark plugs. Have you noticed an intermittent loss of power? Did a check engine light reveal a misfire? Oil leaks from the valve cover are a good place to check first.

Changing a Valve Cover Gasket

A mechanic wearing a black nitrile glove installs new spark plug tube seals. — Double-check the spark plug tube seals to ensure they are properly seated.

eBay has a detailed step-by-step guide and video for changing a valve cover gasket - opens in new window or tab. .

It's a relatively simple job that can usually be done in less than 30 minutes. Here's a summary of how to complete the job. To get started, make sure the engine is completely cool. Start by removing any components blocking the valve cover and locating the cover bolts. Carefully remove the bolts using a socket wrench and lift the cover, taking care to note where the gasket is located.

Remove the old gasket and discard it, then clean the surfaces where it will sit on both the engine and valve cover. You may need to apply a layer of RTV silicone gasket maker if your cylinder head has any sharp or tight curves. After this is done, put the new gasket in place along the edge of the cylinder head and replace the valve cover. Hand-tighten the valve cover bolts in a criss-cross pattern before you torque them down. This ensures that the pressure is evenly applied. Then, tighten the bolts to the torque value in the repair manual for your model.

How much does it cost to replace a valve cover gasket?

A replacement valve cover gasket costs between $20 and $100, depending on the make and model of your vehicle. If you are planning on doing the labor yourself, this will be the extent of the project cost.

However, if you go to a professional shop, the cost of labor could be between $200 and $400. If your valve cover requires a lot of labor to remove parts in the way, the price could be even higher.

What to Replace While Changing a Valve Cover Gasket

A mechanic wearing a blue nitrile glove holding two spark plugs, one used, one new. — You should consdier swapping in a set of fresh spark plugs when replacing valve cover gaskets.

While you have your valve cover off, there are a few things to check. The most important components to look at are the spark plugs, spark plug wires, and ignition coils. If your valve cover was leaking, these parts may have been damaged. With everything already pulled apart, this is a great opportunity to change them.

Sometimes, your valve cover gasket will have integrated spark plug tube seals. Even if they are separate from the gasket, it is a good idea to change them at the same time. If the gasket has deteriorated, the odds are good that the tube seals are compromised. Change them to ensure a tight seal and optimal engine operation.

About the author

Michael O'Connor

Michael O’Connor is a Bay Area writer who grew up restoring classic cars. These days, he works on his 1979 Fiat Spider. Michael is an alum of Sonoma State’s Creative Writing program. He began professional auto writing in 2015, contributing to AutoList, CarGurus, Endurance Warranty, Safe-Guard, and other car sites.

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This article is meant to provide general guidance only. Automotive maintenance, repair, upgrade, and installation may depend on vehicle-specifics such as make and model. Always consult your owner's manual, repair guide for specific information for your particular vehicle and consider a licensed auto-care professional's help as well, particularly for advance repairs.