I am going to talk about the most misdiagnosed oil leak on BMW E46 M3. Usually, people mistake it for oil pan gasket, valve cover gasket, or rear main seal.
You can see there’s a little bit of oil leaking from right here, it could be the rear main seal or the oil pan gasket, you need to check out that CPV o-ring which is all the way up on top of the block
I post a picture if we can find one of one with the you know the actual engine out of the car
You can see where I’m trying to get it out from that way that should help you position yours once you have it loosened I want closest to the passenger frame rail went through the opening above the headers and above the cats
Put a cut this o-ring, got a section cut through it then you just pull it right off
Replace the new o-ring, you might have a little bit of oil seep out from where this valve was just clean that up before you put the valve back in, clean up all the threads, the area on the block where the sits in before you put it back in
Make sure you use a Viton o-ring that we don’t have to do this again and obviously if you have like countless headers or anything this is a lot easier.