Crankcase Oil Separator - E90 325i/330i, E60 525i/530i, E85 Z4 3.0i/3.0si

The BMW N52 engine was deisgned with a crankcase vent system that relies on a heated oil separator valve to separate vapor from the liquid oil. Under ideal circumstances, the oil vapor would pass back into the intake and get burned up during normal combustion. The liquid oil would follow a path back down into the oil pan and be reused. This system is environmentally friendly but plagued with problems. The heating elements can fail or solid oil and carbon particles can block the oil separator valve. With no escape, the oil will continue to pool and collect in the valve cover or make its way into the combustion chamber leading to excessive oil consumption, blue smoke from the exhaust, idle and running issues. These issues are worse in colder climates where the freezing temperatures create a oil sludge condition that is impossible to clear. Thankfully, the CCV is replaceable on the early N52 engines (2006) and should be inspected during a major service and any time the valve cover is off. Oil can also back up into the throttle body, which is easier to check than the oil separator itself. Later N52 engines do not have a serviceable oil vent as it is integrated into the valve cover and not a separate part.

The oil separator can be replaced on its own but for a complete service we also recommend replacing the oil separator hoses and cleaning the valve cover. Any valve cover or intake manifold work should include a new oil separator valve.

This item fits the following BMWs:
2006-2011 E90 BMW 325i 325xi 330i 330xi - Sedan
2006-2012 E91 BMW 325xi - Wagon
2006-2007 E60 BMW 525i 525xi 530i 530xi
2006-2008 E85 BMW Z4 3.0i Z4 3.0si