Genuine OEM Volkswagen Coolant Hose, part number 1T0122157AF. This hose is a critical component in the engine cooling system, responsible for transporting coolant between various engine parts to maintain optimal operating temperature. It is located in the engine bay, as indicated by its position in the diagram. Genuine OEM coolant hoses are manufactured to precise specifications, ensuring correct flow rates and resistance to heat and pressure, which is vital for preventing leaks and engine overheating.