johnny5

So I have a question I was just doing some work on the car and removed the intake manifold and noticed quite a bit of oil that came out of that box underneath the air tube near the throttle body. I’m assuming it’s some sort of factory catch can??? Anyways had a bit of oil in the intake manifold as well as in the air box which got onto the air filter. Would this be the Oil Seperator Cover Crankcase Vent Valve that could be on its way out? I hear that some is fine but I think this is a bit excessive. Another way to figure this out and correct me if I’m wrong is that while the cars running can’t I remove the oil filler cap and see if it has vacuum which I believe should not be the case on these cars?

Any advice or help would be great. Thanks

CaliBenzDriver

John, its interesting you find that li'le factory catch can right outside the throttle body . Just like you, I've wondered what this was and where the oil came from.
Normally most of that engine oil travels through the intake plenum into cylinders. The left over gets stored in the intake and gets to spill outside into said catch can

Unfortunately the PCV centrifuge does not stop much oil vapor even perfectly new. It's not supposed to stop all the crankcase pressure from escaping. This would force more oil to escape outside from every where else. Some people report dipstick popping up, valve cover leaks, CPS feeding oil in the harness.

As it turns out, starting tomorrow I will be testing a way to keep engine oil substantially cooler than its vapor state.

johnny5

Sorry for the delay. I figured that was what it was as it had a pretty good amount of oil in it. I’m sure I got a good amount out when it was tipped upside down so I’m wondering if that will help with it getting oil into the air filter housing. I didn’t notice it last time I changed out the air filter but this time I did. Wondering if it’s something we should be cleaning out as a maintenance item? I was just curious if I pull the oil fill cap if it has a pretty strong vacuum and if it doesn’t don’t think that’s normal? But not sure how Benz does its system. So curious if others has detected this as well?

Keep me posted on what your able to find out and if you were able to minimize the oil in that catch can.

Thanks for the response by the way!

ChrisHimself

it just does that, you should see what my BMW would vent under boost. You could leave it for ages it wouldn't really hurt anything but the plastic on the airbox probably isn't oil resistant