The crankcase ventilation valve has an oil separator on the bottom of it. The separator uses a cyclone action. So, I could see how someone could call it a cyclone valve, maybe even BMW does, not sure.

The oil separator/crankcase ventilation valve is not the cause of the white/yellow pasty stuff under your oil filler cap. That residue is caused by too many short trips, the engine not getting hot enough to burn off the condensation, etc. That same stuff causes problems with the crankcase ventilation valve, when it freezes in the lines. So, someone was confusing cause and effect when they told you the valve caused this, IMO.

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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