Thanks to advanced wetting agents, VP Cool Down™ is the best engine coolant additive for reducing coolant surface tension. It delivers exceptional heat transfer in radiators and reduces nucleate boiling in cylinder heads.  Cool Down helps prevent overheating and lowers engine temps (by up to 30°F!). It lubricates all vital components, including water pumps and seals, and prevents corrosion and electrolysis of all metals, especially aluminum. Cool Down meets/exceeds ASTM D3306 specifications established by OEMs for engine coolant. It's ideal for use as a gas or diesel coolant additive and perfect for racing, street vehicles, RVs, & towing applications.  Take a look at what happened when Engine Labs put Cool Down to the test on a 2006 C6 Corvette.