Genuine OEM Audi Engine Coolant Hose, part number 4G0121448AK. This hose is designed to transport coolant efficiently within the engine cooling system, playing a vital role in maintaining proper operating temperatures. It is a short, curved hose, highlighted as item 21 in the diagram, connecting to the expansion tank. Weighing 0.058 kg and measuring 0.205 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.