Genuine OEM Audi Rear Engine Vent Hose, part number 8K0121081AL. This hose is a crucial component designed to allow gases to escape from the engine, contributing to proper engine ventilation and maintaining balanced internal pressures. It plays a role in the overall health and efficiency of the engine system. This hose is positioned at the rear of the engine assembly, connecting to the expansion tank. It measures approximately 0.12 meters in length and weighs 0.026 kg. Using a genuine OEM vent hose ensures the correct material composition and precise routing, preventing leaks and maintaining the integrity of the engine's ventilation system.