I have an 07 335i ST w/151k, car runs great on jb4/BEF. Upgraded to external catch cans/BL coils and while swapping plugs found cylinders #1 completely cover in oil. Proceeded do a compression test dry/wet cold/warm/hot compression was perfect. Barrowed a leakdown tester and also passed with flying colors. I hate to throw money at it without knowing exactly what’s wrong with it. Few things I noticed, car seems to be getting a lot of blowby, burning through oil but not a lot of smoke, see the occasional puff at start up. When you open up the oil fill cap seem to have excessive crankcase pressure. Can this be cause by a cracked internally or bad seal VC? Any ideas are welcome. Really appreciate the help.
Dunno but the oil on threads suggests it may have leaked down from the spark plug well. But I can't figure how oil -- most possible from a tired valve cover gasket -- would have leaked down onto the plug like that unless the spark plug was way loose.