Finding the source of leaking motor oil can be difficult. Leaking valve covers are often diagnosed by a burning oil smell while driving, along with oil-covered valve covers. Valve covers will only leak motor oil when the engine is running; unlike the oil pan which can leak at any time. Sealing a leak in the valve covers requires a small amount of troubleshooting. Valve cover bolts can loosen over time, causing a leak, or the valve cover gasket can wear out. In either case sealing the valve covers is imperative to engine health.
Consult your vehicle's owners manual to find the torque requirement of the valve bolts. The torque wrench will have a foot-pound measurement dial on the top. Turn the dial to the correct foot-pound amount. Tighten the valve cover bolts.
Clean the oil from around the valve cover. Top off the engine oil if it is low. Drive the car for approximately 15 minutes. Check the area around the valve cover for fresh oil; if none is seen it's likely that the valve cover bolts were loose. If you see fresh oil the valve cover gasket will need replacement.
Allow the engine to cool and remove the valve cover. Each car is different and may require the removal of spark plug wires, PVC hoses or throttle cables. Place a tent of old newspaper or a towel over the engine to prevent nuts, bolts or debris from entering the engine.
Clean the area around the valve cover and the valve cover itself completely with shop rags. Remove the old gasket and rubber sealant from the valve cover using a plastic tool. Do not use a metal tool to scrape the valve cover; doing so may cause divots in the aluminum, creating a new source for leaks.
Align the new valve cover gasket with the valve cover. Pay special attention to the instructions on the valve cover and place it facing the right direction. Apply silicone to the areas specified on the valve cover gasket instructions. Silicone is meant as reinforcement for the gasket and should only be applied where necessary. Allow the silicone to "set-up" according to the time limit on the back of the tube.
Reinstall the valve cover. Tighten the valve cover bolts using the correct amount of torque. Replace the hoses and other parts removed to access the valve cover.
