Genuine OEM Toyota Radiator Hose No.1, part number 1657137210. This hose is the main conduit for coolant circulation between the engine and the radiator. It is typically located at the top or front of the radiator assembly. Constructed from high-quality, heat-resistant rubber to withstand engine operating temperatures and pressures. Genuine OEM parts are essential for maintaining the precise flow rate and integrity of your cooling system, preventing leaks and ensuring optimal engine temperature.