Genuine OEM Volkswagen Engine Coolant Hose, part number 5R3122109. This hose is responsible for transporting engine coolant, playing a vital role in regulating engine temperature and preventing overheating. It connects the coolant expansion tank to the rest of the cooling system. The hose has a length of approximately 25cm. A genuine OEM coolant hose ensures the correct material composition, heat resistance, and precise routing geometry for optimal cooling system performance and leak prevention.