Genuine OEM Audi Coolant Hose, part number 420121101D. This shaped hose is a vital part of the engine's cooling circuit, designed to transport coolant to and from various engine components. It is positioned within the engine bay, connecting to the cooling system in the vicinity of the alternator. Made from durable, reinforced rubber, this hose weighs approximately 0.556 kg. Using a genuine OEM coolant hose guarantees the correct material composition, precise bends, and connection points, which are crucial for maintaining system pressure and preventing leaks under engine operating conditions.