This lower radiator hose carries coolant from the engine block to the radiator core, completing the return leg of the cooling circuit. It is formed with multiple internal diameters to match the stepped ports on the radiator and engine connections, maintaining flow velocity across the transition. A collapsed or softened hose restricts coolant circulation, causing the engine to run above its normal operating temperature. The hose is constructed with a fabric-reinforced rubber wall that resists pressure pulses from the water pump and withstands the temperature range of the cooling system. When replacing, ensure each clamp seats fully on the rigid nipple behind the hose bead and tighten to the specified torque to prevent seepage.