Genuine OEM BMW Crankcase Ventilation Vent Pipe, part number 11157642546. This pipe routes harmful gases from the crankcase, allowing for proper ventilation of the engine's internal environment. It is a key component in the crankcase ventilation system, helping to reduce pressure and prevent oil contamination. The pipe is constructed from durable, oil-resistant material. Genuine OEM parts ensure the correct internal diameter and routing for optimal ventilation performance and engine longevity.