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.
