Suggestions? valve cover

[xmillionn]

A friend bought a 2004 Z4, 3.0 - 6 weeks ago, with 118k miles and love it. Oil leak at rear passenger corner of valve cover - oily and smokey - caused me to replace the gasket. There were no obvious signs of leaking at the machined head when cover removed. However, there was a fair amount of oil on top of the cover after decorative shroud was removed and spark plug #2 was full of oil. Caused by leaking at interior gasket or what? Suggestions?

[Z4Mariner]

I don't own a car with an M54 engine at the moment, but the valve cover (VC) gaskets are notorious for getting brittle with age, and a leak from the interior gaskets that seal the spark plug wells would not be uncommon.

Did you replace the gasket set with the interior spark plug well seals? If you did and it solved the issue, great ! If a replacement failed to solve the issue, my check list would be: 1) Did I pinch a gasket ? 2) Did I replace the grommets on the VC bolts ? 3) Do I have a cracked VC ?

The grommets on the VC bolts compress to properly seal the VC, and old, brittle ones may not perform properly. Cracks in the VC are also possible - sometimes they can be patched for a while with sealant, and sometimes not. You will find a lot of discussion of this topic on E46 forums with large memberships.

Hope this is of some help.

[colb]

Z4mariner covers all of the causes of cam cover gasket replacement. Important to use new round rubber seals on the cover bolts old ones go hard and don't compress enough to provide correct seal. Inspect the plastic cover for cracks and signs of the plastic crumbling,seen a bad case of this on a 2.2 Z3. Leaks will also let air in and play havoc with fuel trims