Genuine OEM Hyundai Radiator to Reservoir Hose, part number 25451K4320. This essential cooling system component is responsible for transferring coolant between the main radiator and the coolant expansion reservoir. It plays a vital role in maintaining proper coolant levels and system pressure. Using a genuine OEM hose ensures the correct material composition for resistance to heat and coolant chemicals, precise routing geometry, and durable construction for leak-free and reliable performance under engine operating conditions.