Crankcase Vent Hose, BMW - E46 M3 01-04, MZ3 S54

This part is listed by BMW as BMW part number 11157831311 (11 15 7 831 311) and is described as a crankcase oil vent hose from the valve cover to the intake manifold on 2001-2004 E46 M3 and MZ3 (S54). The oil separator and vent tube may be cleaned but a complete replacement is the only sure way of getting the S54 oil vent system back to normal operation.

This plastic vent hose carries oil vapor from the cylinder head/valve cover to the intake manifold where it is then mixed with the intake air and burned in the engine. This is how the S54 crankcase vent system is supposed to work. But over tens of thousands of miles, the oil separator in the valve cover and this vent tube on top of the engine get clogged with oil and carbon and this reduces its effectiveness. A clogged or malfunctioning crankcase vent on the S54 will lead to excessive oil consumption (too much oil is getting burned), fault codes for fuel trim, misfires, and rough running.

This is a Genuine BMW S54 oil vent hose with a two year warranty. Buying a Genuine part will usually be more expensive than an OEM or aftermarket brand but you are assured that it meets BMW's designs for fitment, performance, and longevity. It will also be the very latest design, incorporating any updates or revisions that an aftermarket brand typically will ignore.