Thoro-Flush Radiator and Engine Cleaner from Irontite is designed to remove rust, grease and sludge to help make the vehicle's engine cooling system perform better. According to the company, regular application of Thoro-Flush to an automobile helps extend the life of the vehicle, reduces the possibility of a clogged heater core, and helps keep the cooling system fluid flowing throughout the vehicle’s engine and radiator. It works in 15 minutes, and it can be used on auto and heavy duty truck cooling systems.