Quote:
Originally Posted by JohnelP
Thanks
dealer claims they changed the turbo oil return tubes when they performed the ccp valve stem seals <10k miles ago. I trusted them; so, (maybe i made a mistake) i did not check them....
i see the crank ventilation valves are trivial flap type check valve towards the air inlet to the turbo. I could not see the pcv mechanism towards intake manifold, but i doubt it is fancy stuff.
I just got the vacuum/boost gauge, and i will check the crank pressure. i see from other's shared experience that the crank pressure varies a lot during different engine running conditions. i'll see where my engine stands; however if the crank pressure would be an issue, then driver side diverter valve should have oil, not only the passenger side.
though i think i may end up with two catch cans on both sides, and see if they collect same amount of oil..
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Ya it looks that way but its actually the one of most complex CCV system BMW has ever designed. Embedded in T connection that goes to the lower CCV tubes is a special 2-way check valve that limits CC pressure at idle & part throttle non-boost conditions to about -1 psi, then under boost this valve shuts and redirects all CCV gases to the upper intakes/turbo inlets via the one-way check valve flaps that open and take over. Adding catch-cans is highly recommended as the oil/air separators in the valve covers are a joke. You will be shocked how much oil they catch (choose catch cans with sintered bronze 50 micron filters)
I did a deep dive on all of this years ago, if you search for catch cans on this forum you will find a ton of posts over the years from me and other members about addressing this issue along with going hard-core and adding your own adjustable one-way valves to increase CC vacuum past the paltry -1psi bmw has it set to. I run mine at -10ish psi. No more oil leaks from the rear main or anywhere else now for the past near 90k miles I have been running it, even at 182K miles now on the engine. BMW and other manufactures don't run this high of negative CC pressure as replacing gaskets for oil leaks is major $$$$$.
Under full boost you should not see any pressure or perhaps maybe 1psi max in your crankcase. Even mine with how many miles I have on the engine and running 18-21psi of boost I don't see more then 1psi Crankcase pressure under full boost at the end of a 1/4mile run. Anything more then that indicates bad check valves in your CCV system or excessive blow-by.
After you have you are sure your CCV system is good and running catch-cans still have oil out that side, only option left is to pull the turbo and check the oil return line to double check dealers work and if that checks then most likely turbo seals which you can find rebuild kits for.
EDIT: Here is one of the threads I was referring too:
https://www.xbimmers.com/forums/show....php?t=1731029