I have a 190e Mercedes 1988, it's great condition. I problem, I have oil leaking out through the oill cap. I've had the valves checked they are OK. I changed the oil cap but oil is still seeping through. I checked the breather filter (the little white filter) and that was OK. I asked the guy at the Mercedes dealership and he told me that the cap may not be sitting flush. I filed down where the cap screws in to make sure I had a smooth surface. Any ideas? Engine has only 70,000 miles.

 

Two things come to mind to check.
If they are ok, then we can move on and check other things.

1) The rubber preform tube that goes from valve cover to intake manifold (part# 1030940082): Check to see that it is an original MB tube, and that it is not collapsing due to vacuum when you rev the engine. Reason: sometimes people replace the tube with a peice of hose, and it simply gets sucked closed most of the time, which effectively blocksthe pcv flow. Also make sure both ports are clear of obstructions.

2) Hopefully your piston rings are ok. Do a compression check to confirm that the rings are sealing. "Blow-by" can pressurize the crancase. Blue

 

Problem likely caused by Crankcase Pressurisation caused by ineffective breather or piston blow by.

If the crankcase is pressurised then likely you will have other leaks!

Do as blueSilver suggests first.

I assume oil level is correct i.e. Not over filled (and correct dipstick)?

Stuart

 

check fluid level first, second ive heard the return ports can get cloged not letting oil flow back down