Decel exhaust smoke (pcv, vc crack, turbos)


Dec 16, 2017
135i, 330i
I've accepted the worst already but I'd like to see if anyone could help me entertain what would be a miracle, relatively speaking.

My 135i had a new N54 professionally installed after spinning a rod bearing- reused turbos (30k old from BMW ext recall). All lines were put through parts washer.

The car is burning oil, typical turbo seal failure behavior, blowing smoke at decel and if you hold the throttle at 1200. Car looks like it is on track to consume about a quart per thousand miles but it may just still be populating my oil coolers. It has a new RB PCV valve. Although all the gaskets were replaced, it appears there are two leaks on the inside valley of the vc by cylinder 3 and 5. I'm suspecting the vc is cracked.

I suppose the quickest answer I'll get to this problem is to peak underneath and maybe pull the dps, but I should probably tend to the vc sooner than later anyway. Is a cracked vc possibly my problem? It pisses me off to think the turbos might've pissed oil during the swap and the shop didn't bother proposing to replace them then. The silver lining to this situation is that I have a good condition VC on the blown motor that's sitting in my garage.


Jan 28, 2018
Parts unknown
07 335i
A leak down test is in order. Most likely the valve seals if smokescreen is on deceleration I had this same issue. You may be lucky and its the turbos and not the reman engine.
Step 1.)Downpipes.
Step 2) pressure up and leak down. This may even hiss out the VC.