Genuine OEM Audi Coolant Hose, part number 8K0819373. This hose is a vital part of the engine cooling system, responsible for carrying coolant between various engine components, including connections to the heater system. It ensures efficient heat transfer and helps maintain optimal engine operating temperatures. Choosing genuine OEM guarantees the correct routing geometry, material composition, and resistance to heat and pressure, preventing leaks and ensuring reliable cooling system performance.