Q: Plugs get oil on them and misfire

asked by on May 31, 2016

The plugs in my car keep misfiring. For some reason, the plugs under the coil are getting oil on them. I was wondering what can cause this. My car has a North Star, 4.6-liter engine. Do you have any idea what the underlying issue is? Thanks.

The top most part of your engine is called the valve cover. On a V-shaped engine, you should have 2 valve covers. These valve covers are bolted to the top of the cylinder head and have gaskets in between the two mating surfaces to keep oil from leaking out.

In the center of your valve covers should be 4 holes in each one. These holes represent where the spark plugs are inserted into their sleeves. The valve cover gasket set comes with what are called spark plug tube seals which go around the sleeves to prevent oil from getting onto the spark plugs. These tube seals can go bad just like the valve cover gaskets can and will occasionally require replacement. Unfortunately, even if the valve cover gaskets are not leaking and the tube seals are, the valve cover gaskets will still have to be replaced as the valve covers will need to be removed to access the tube seals. I would recommend having this job performed by a certified technician for best results.

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