Genuine OEM Volkswagen Coolant Hose Assembly, part number 5N0122109AA. This critical component is responsible for circulating engine coolant between various parts of the cooling system, such as the radiator, engine block, and heater core, to regulate engine temperature. It is installed within the engine bay as part of the complex cooling circuit. Made from durable, heat-resistant rubber and plastic, this assembly weighs approximately 0.443 kg and measures 0.56 meters in length. Choosing a genuine OEM coolant hose ensures correct routing geometry, material compatibility, and resistance to thermal cycling and pressure, preventing leaks and maintaining cooling system integrity.