Genuine OEM Audi Coolant Hose, part number 8K0121030A. This hose is a critical component in the engine cooling system, responsible for transporting coolant between the radiator and other engine components. It is positioned within the main radiator circuit, connecting to the lower section of the radiator. Constructed from durable, heat-resistant rubber, it weighs approximately 0.198 kg. Choosing a genuine OEM coolant hose ensures correct routing geometry, material integrity, and resistance to temperature and pressure fluctuations, preventing leaks and system failures.