STP Radiator Sealer quickly and effectively repairs radiator leaks by forming a permanent seal while protecting your cooling system from rust and deposits. It also lubricates the water pump, helping your engine run smoothly. Compatible with all types of radiators and antifreeze, this easy-to-use formula works in just minutes—simply add to a warm radiator, run the engine briefly, and let it seal. One bottle treats cooling systems up to 14 liters, keeping your radiator leak-free and corrosion-protected.