Description:Crankcase Pressure Regulator Valve OEM:11151406789 Used in vehicles: BMW material:plastic Crankcase Pressure Regulator Valve - Cylinder Bank 5-8 (Driver) Commonly referred to as the "oil separator" BMW has an issue with oil separators freezing in cold weather if the engine is not fully warmed up during driving. Common symptoms are a howling noise followed by oil leaks.Crankcase breather valve used to purge the oil vapor from the engine block into the valve cover. This valve has 3 hoses connected to it, running to dipstick, valve cover, air intake.You should also look into replacing your valve cover when changing the separator .