Granville Rapid Cool Red Antifreeze and Coolant is an ethylene glycol based engine coolant concentrate, which uses Organic Acid Inhibitor Technology (OAT) and is free from nitrates, amines, phosphates, borates and silicates. Granville Rapid Cool has a 5 year or 250,000km life and should be changed whichever is the sooner. Unlike traditional coolants which employ inorganic inhibitors, Rapid Cool Red has excellent hard water stability and very low inhibitor depletion rates.