I'll vote with the other guys that there's a real good possibility that it's a flame trap problem.

I learned the hard way -- it's so #@* hard to get to on both my 240 and 940 that I got lazy and eventually the blown oil seals on my 940 convinced me to check them at least every-other oil change.

BTW, bought two kits from IPD that were supposed to move the flame trap to be more easily accessible -- were worthless. The hoses were not formed right.

I'll mention a problem I had on an 87 20dl. My engine started leaking around the valve cover gasket. I changed it and then the leak showed up at the oil filler cap. So I made a gasket so it would be tight to stop the leak. then it started leaking from the valve cover again. then by chance, I unscrewed the cap and noticed a puff when I got it open, as if it were under pressure. I then checked the pcv valve and it was clogged solid. the engine would normally blow off the internal pressure into the pcv valve which the intake hose would suck up. the pcv valve is not a replaceable valve.
You have to soak it in a solvent to clean it. carb cleaner worked good. after that, no more leak.

Check the oil pressure sensor next to the oil filter. They have a tendancy to leak. Also check the oil filler cap for a leaking seal. The most important thing to check is the flame trap and the associated plumbing for blockage, which might be the cause of some of your oil leaks.

Mario
--
'I've always been crazy, but it's kept me from going insane' Waylon Jennings