<strong>Yahoo Message Number: 104656</strong>When flushing the cooling system I need to use a cleaner to remove any possible rust or scale. Caterpillar sells an outrageously expensive fast-acting cleaner for $50 a gallon! Cats is citric acid an ethanol based. What have you all used? Prestone is citric acid based but does not contain ethanol. There's also the stuff made by fleet called...