Genuine OEM Toyota Engine Water Bypass Hose, part number 1626724040. This hose is part of the engine's cooling system, allowing coolant to bypass the radiator during cold starts to help the engine reach optimal operating temperature faster. It plays a role in efficient engine warm-up and emissions control. Located in the engine cooling system. Constructed from reinforced rubber or silicone to withstand high temperatures and coolant pressure. Genuine OEM hoses are designed with precise internal diameters and routing for proper coolant flow and system integrity.