Why Does the Valve Cover Gasket Keep Leaking Oil After Replacement?

[OSavannah]

The reasons for continued oil leakage after replacing the valve cover gasket include the following: 1. The crankcase forced ventilation valve is blocked, causing increased crankcase pressure, which then releases through the valve cover gasket or other weak points, resulting in oil leakage. 2. The valve cover gasket has aged, leading to poor sealing. 3. If the crankcase ventilation valve is clogged, or if the piston rings and cylinder wall gaps are too large, causing excessive blow-by gas, the high crankcase pressure will force gas to escape through weak sealing points, such as the valve cover gasket or front/rear crankshaft oil seals, resulting in engine oil leakage.

[OJason]

My previous car had a similar issue. After replacing the valve cover gasket, it leaked oil even worse. Later, I found out it was because the gasket wasn't installed properly—uneven or overly tight screws can deform it. Over time, the engine base may warp slightly, and if the new gasket doesn't fit snugly, it won't seal properly. Make sure the cleaning job is thorough; leftover oil residue has a big impact. DIYers often overlook details, so it's best to have a professional shop handle it. Also, part quality is crucial—cheap gaskets use inferior materials that degrade and shrink under high heat. Ignoring this can lead to oil buildup corroding engine parts and higher repair costs. Regular maintenance can prevent such headaches. After installing a new gasket, drive a short distance and recheck the tightness to ensure everything's secure.

[VonMicah]

I've seen many such cases during repairs where customers often complain about oil leaks even after replacing the gasket. This is usually caused by screws being either over-tightened or too loose, resulting in uneven sealing. Before installation, the surface must be thoroughly cleaned of oil stains, preferably wiped clean with a professional cleaner. Cheap parts tend to crack quickly, especially under high temperatures, and are prone to failure—always use OEM or high-quality parts. If the engine is old, the cylinder head might have slight deformation, requiring the base to be repaired before installing a new gasket. Otherwise, small issues can accumulate into major problems, such as oil affecting the spark plug holes and causing ignition failures. Spending a bit more to find a reliable mechanic to get it done right the first time saves a lot of hassle.

[Pete]

Just a few days after replacing the valve cover gasket during the last car repair, it started leaking oil again. So frustrating! The installer probably didn't thoroughly clean the residual grease on the engine surface, which prevented the gasket from sealing properly. The quality of aftermarket parts also seems inconsistent - cheap ones can't withstand high temperatures and age faster, especially with frequent short trips causing significant engine temperature fluctuations. Oil leakage isn't just a gasket issue; it might indicate deteriorating engine oil or internal component wear. Better get it checked early to prevent worse consequences like strange odors or smoke.