When you think of BMWs, you generally don’t think “oil leak,” which is usually a problem associated with ageing British cars rather than highly engineered German cars. But like any car, a BMW can develop oil leaks, particularly around the valve cover gaskets at the top of the motor. Replacing the valve cover gaskets on a BMW E46 3 Series is relatively straightforward with the proper tools and approach.
Remove the engine covers. The covers are held on with bolts concealed by small, round, plastic covers that need to be pried out. Remove the 10-mm bolts with a socket.
Disconnect the clips that hold the wiring harnesses to the coil by prying them upward with a screwdriver. Unfasten the clips that hold the wiring harness for the coils to the engine by prying them up with a screwdriver.
Move the wiring harnesses for the coils out of the way. Remove the coils by unbolting the two 10-mm bolts that hold each one on. Remove the grounds for the coils, noting where they fasten to the engine. Pull the coils out of the engine’s head. Label the coils with a piece of tape and a marker so you know which cylinder they go to for reassembly.
Remove the 15 valve cover bolts with a 10-mm socket. Keep track of where each bolt goes as they are not all the same length and need to be reinstalled in the same order. Remove the valve cover by tapping it gently with a rubber mallet while pulling the valve cover up with your fingers.
Remove any excess gasket material left on the head. Remove the old gasket from the depression in the valve cover.
Clean the valve cover and the head where the valve cover installs with brake cleaner and a shop rag. Place the valve cover upside down and install the new gasket into the cover. Apply a small film of RTV sealant to the corners of the valve cover gasket, but do not apply the sealant to the entire surface.
Reinstall the valve cover on the head before the sealant dries. Ensure that the gasket is still in the proper place and then tighten the bolts that hold the valve cover in place in “Z” pattern, working your way back and forth from bolt to bolt to progressively tighten the bolts. Tighten all of the bolts progressively to 89ft/lbs with a torque wrench.
Reinstall the wiring harness for the coils with the clips that hold the harness in place. Reinstall the coils into the head by sliding them down over the spark plugs. Reconnect the wiring harnesses to the coils with the two 10-mm bolts. You only need to tighten these to about 10ft/lbs. Start the motor and check for leaks. Reinstall the engine covers and the small plastic covers that conceal the engine cover bolts.
When removing the valve cover, tap it with the mallet slowly and gently so that you don’t dent it. Do not use a sharp metal object to pry the cover off as this may scratch the head.