My 1990 244DL has recently developed an oil leak at the rear of the engine. Hopefully, someone with more leak experience than I can help me diagnose the origin of the leak. I have checked the archives (got good info on repairing but not diagnosing) and believe it is probably either the valve cover gasket or rear cam plug. The flame trap has been replaced and is clean.

This is the lowdown:

First noticed the puddle where the tranny connects to the engine. Not too big, not losing much either - not yet anyway!!! Immediate thought was the rear main seal as the car has 206K and the rear main is original to the best of my knowledge or possibly a tranny leak - doubtful, I believe it is engine oil. Then I traced a flow higher up that seems to be emanating from the back of the head and in and around cylinder #4. How can I be sure what it is? Should I replace the valve cover gasket then do the plug if necessary since I'm already there?

Thanks to all,
Jim 1990 244DL 206K and running strong