Crankcase Oil Separator and Vent Hose Kit - E90 325xi/330xi, E60 525xi/530xi

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 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 an oil sludge condition that is impossible to clear. The plastic hoses can become brittle and crack which leads to vacuum leaks and oil leaks. Thankfully, the CCV is replaceable on the early N52 engines (2006 and some 2007 models) 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.

This is a kit containing the oil separator, the vent hoses, and the intake manifold gaskets that are done during a typical oil separator replacement. Complete kit includes:

11617531423, Genuine BMW oil separator

11617559530, vent hose

11157522931, oil separator hose

11157567802, return hose

11157537701, extraction hose

11617547242, intake manifold gaskets (set of 6)

The intake manifold must be removed to access the oil separator so new profile gaskets are included. We also recommend (but not required) a new oil separator fitting on the intake manifold because it's one of the heated elements that vaporizes the oil as it enters the intake.

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 kit fits the following BMWs:
10/2005+ E90 BMW 325xi 330xi - Sedan
10/2005+ E91 BMW 325xi - Wagon
10/2005+ E60 BMW 525xi 530xi