Bad Valve Cover Gasket Effects. Symptoms Of Bad Valve Cover Gasket 1. An engine oil leak is the most common sign of a bad valve cover gasket.
As the gasket works as a seal it takes the most pressure and hence there is a fair chance that it wears and tears. Low Oil Level A leaking valve cover gasket can eventually lead to a low engine oil level. I know some engines will run bad when there is any kind of bad seal.
Obviously an oil leak will be the main problem with a bad valve cover gasket.
Valve cover is dirty and leaking oil. In an otherwise normal engine with good compression rings and valve guides bad seals will cause a loss of oil that can be detected on the oil dipstick. Your valve cover gasket may be leaking for a variety of reasons. If not changed you run the risk of causing some damag.