I don't think a CCV valve with an oil separator is cheaper than a PCV valve.

The OS is a more technically complete and elegant solution. The engine oil is separated out of the crankcase fumes, and returns to the sump, instead of being sent into the combustion chamber. It comes with a downside, which is that it is harder to maintain than a PCV valve (which we used to just throw away and replace).

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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