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Valve Cover Oil Leaks

by Bill C. -

SYMPTOM: You just replaced your valve cover gaskets (air-cooled engine), perhaps after adjusting your valves on that latest oil change. You now have an oil leak at the bottom of your valve cover(s), which is running down over your heat exchanger(s).

 PROBLEM: You probably have what I call a “bowed” valve cover gasket. I have found that these gaskets vary ever so slightly in size, especially the measurement around the outside (circumference). It can be more critical if you run aluminum valve covers that are thicker and are not as forgiving due to dimensional variations.


With the valve cover off, laying on the floor or whatever, test fit by placing a new gasket into place. Is it real “tight” and tends to buckle or bow? If so, use a pair of shears (heavy duty scissors, available for $4-5 at Home Depot tool dept.) to trim down the outer edge by about 1/16”-1/8” and test fit the gaskets again. If that does it, go ahead and bolt or snap the covers into place, being very careful not to knock the gasket out of place on the rocker arms.

One other thing, make sure you cleaned off any cork left on the gasket mating surfaces from the OLD gasket before installing the new gaskets. And I seem to have good luck with NOT using any gasket sealer. It saves the clean up when you have to change gaskets and you won’t run the risk of getting old gasket pieces into your rocker arm area.