Genuine Gates Lower Radiator Hose - 3318 Your vehicles cooling system plays a vital part in the smooth running of your engine. Coolant runs through the various pipes and hoses passing through the engine to help keep it at a reliable temperature. Over time hoses begin to fray and crack, which can lead to leaks and potential engine damage. Replacing your radiator hoses regularly will help ensure your engine runs at optimal temperatures and prevent costly repairs.