Genuine OEM Audi Engine Coolant Hose, part number 04L121157AQ. This hose is designed to transport coolant within the engine cooling system, playing a role in heat exchange by connecting to the oil cooler. It is a short, curved hose, highlighted as item 3 in the diagram. Weighing 0.0612 kg and measuring 0.16 m in length, it is engineered for precise fitment. Using a genuine OEM hose ensures correct routing, material integrity, and resistance to temperature and pressure fluctuations for reliable cooling performance.