The OEM BMW plastic PCV valve does not hold pressure well even when brand new. What the leaky PCV valve means is that when you are in boosted conditions, the “highly” pressurized PCV valve leaks turbocharged pressures into the crankcase. Depending on the condition of your PCV valve it could leak worse than others. Also if for some reason your valve cover is cracked, loose, or has a bad gasket; you also could develop a pressure leak either external to the engine or internal into the crankcase causing further pressurization of the crankcase or other oil loss issues.

Priced per valve.