Keep your car radiator cooling system in peak condition, with STP Radiator Flush. Over time, rust and dirt can build up in your car’s cooling system. If your coolant gets too contaminated, it cannot cool or warm your engine efficiently to keep it at its optimum operating temperature. The result? Summer-time overheating, winter-time freeze-ups and reduced fuel economy. This powerful car radiator flush treatment helps keep your cooling system in peak condition. Its advanced radiator flush formula removes rust and sludge, clearing blocked water channels. Use STP Radiator Flush before changing your coolant or adding antifreeze for a smoother drive and improved performance, whatever the weather.