A valve cover is a metal or plastic part that sits on the top of your engine. Depending on the design of your specific engine, it can have either one or two looking alike valve covers. If you have an inline engine, there is no doubt that it features a single valve cover. In case you drive a car or truck with a V-type motor, you’ll find two valve covers under the hood.
Your valve cover is more than just a piece of metal or plastic built to complete the engine. It does a crucial job, protecting your intake and exhaust valves, valve springs, camshafts and other valvetrain components from dirt, dust and debris. Besides, it keeps your valvetrain properly lubricated and cooled, while preventing oil leaks and withstanding high pressure needed for proper oil circulation. This allows for smooth and safe spinning of the camshafts, which open or close the valves, letting an air/fuel mixture in the cylinders and exhaust gases out of the vehicle.
How can I know that my valve cover is bad?
The most common symptoms of a bad valve cover are oil leaks and, as a result, increased oil consumption. If any of these symptoms are neglected, sooner or later you’ll get your engine overheated and damaged. Let’s check the signs of a bad valve cover to prevent that from happening.
Oil leaks from the valve cover
In most cases, oil leaks are an indicator of a poor valve cover gasket. However, the valve cover itself can also become a source of oil leaks if it gets broken or cracked. No matter whether a small leak or a huge one is detected, it must be fixed by replacing the valve cover gasket or the cover. Even if an oil leak doesn’t affect general oil consumption, drops of oil can damage your rubber hoses and belts. In addition, a gap between the cover and the engine head or a break on the valve cover will allow for collecting dirt and dust on the valvetrain components.
Increased oil consumption
If you have to top up the oil level on a regular basis, you may have a bad valve cover or gasket that is steadily leaking oil. In some cases, your check engine light and low oil level warning light can also come on to alert you of the problem. Whichever the light illuminates, you should shut down the engine once it appears. Don’t try to check the oil level right away, wait for 10-15 minutes until the engine cools down.
There is a smell of burning oil
If an oil leak is big enough to allow some oil to reach hot exhaust or engine parts, the oil will burn, so you’ll notice a specific smell. In many cases, it can be accompanied by smoke coming from the engine or the exhaust. Anyway, you should stop the engine and call your mechanic for a piece of advice.
Misfires and rough engine operation
Depending on the design of an engine, its spark plugs can fit into holes on the valve cover or be placed directly below it. If some leaking oil finds its way to the spark plugs through the holes, this will cause them to misfire, resulting in rough running and poor performance.
Can I drive a vehicle with a bad valve cover?
It is not the best idea to drive a vehicle with an oil leak. However, if the leak is small, causing no oil loss or smoke, you could drive your car or truck in case of emergency. Just keep in mind to check the cover for oil drops and keep the oil level higher than the “min” mark to prevent severe damage to the engine.
How to fix a bad valve cover?
If oil leaks are caused by a bad valve cover gasket, it can be fixed by installing a new gasket. Before installing a new gasket, the valve cover must be properly cleaned to prevent dirt or dust from entering the valvetrain. If the source of the problem is a cracked valve cover, it must be replaced along with the gasket. After installing a new valve cover, all its bolts must be correctly tightened and torqued to prevent oil leaks.
Can I fix it myself?
We would not recommend you to replace a valve cover yourself if you have no mechanical experience and the replacing process involves special tools or disassembly of other engine parts. In other cases, you should tackle the job yourself with a replacement kit or gasket that you may find in just about any auto parts store.