Crankcase Vent Valve / Oil Separator, URO - E36, E39, Z3, MZ3, M52, S52

This is an aftermarket E36, E39, Z3 Crankcase Vent Valve (CCV) made by URO and comes with a two year warranty.

The E36/E39/Z3 crankcase vent valve is responsible for separating oil from the air inside the engine and air intake. Liquid oil is returned to the oil pan while oil vapors are sent to the intake manifold to be burned up during the combustion cycle. It's also known as a a PCV, CCV, oil separator, and a cyclonic separator system. Too much oil in the intake air lowers the effective fuel octane, leads to drivability issues, and causes increased emissions. A completely blocked CCV has the potential for very serious engine failure (hydrolock) if liquid oil ends up in the intake. Signs of a failing CCV include: whistling noises in the intake, blueish smoke in the exhaust, high oil consumption, and thick white or yellow gunk under the oil cap.

The crankcase vent system is complex with multiple rubber and plastic hoses running betwee the valve cover, oil separator valve, and the intake manifold. A failed crankcase vent valve (CCV) is rarely the only thing wrong with the system. The hoses are prone to clogging from oil sludge, cracks, and leaks so we recommend a complete overhaul at the same time or at least a thorough inspection of the rest of the system. Regular heavy acceleration and runs to redline and frequent oil changes will also help keep the system working properly.