My engine was leaking oil through the valve cover and I had to replace the head cover gasket to fix the problem, its relatively simple but a little bit aggravating because its a flimsy rubber gasket that you have to coat with a really thick and sticky sealant. You also have to replace the spark plug wires when you do this because when you remove the old spark plug wires to take off the valve cover they are designed to break, so they aren't going to work if you try to put them back on ( I learned this the hard way ).