Genuine OEM Audi Engine Coolant Hose, part number 4E0121055AN. This critical hose is responsible for circulating engine coolant between various components, such as the radiator, engine block, and heater core. Its specific molded shape ensures correct routing and connection within the engine cooling system. Constructed from reinforced rubber, it is designed to withstand high temperatures and pressures, weighing approximately 0.559 kg. Choosing a genuine OEM coolant hose guarantees the correct material composition, precise routing geometry, and resistance to thermal cycling, preventing leaks and ensuring reliable engine cooling.