The oil filter canister is pressurized with oil, so that isn't the same as the crankcase vent. Make sure that it is actually coming from there, and hasn't just dripped down. If it is coming from the canister, replace the seal.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue