essentially of water citric acid ammonium hydroxide a defoamer comprised of a blend of mineral oils and silica derivatives and an octylphenoxypolyethoxyethanol non ionic surfactant having 30 moles of ethylene oxide per mole of t octylphenol application_number US 29301181 A description the most preferred formulation of the invention is a composition consisting essentially of by weight 59 81 deionized water 20 12 citric acid 18 28 ammonium hydroxide 1 64 of an octylphenoxypolyethoxyethanol non ionic surfactant having the formula str2 and 0 15 of a defoamer comprised of a blend of mineral oils and silica derivatives having a specific gravity of 0 91 0 93 and a viscosity of 1 000 1 800 centipoise measured at 25 u00b0 c using a 3 spindle at 20 rpm the entire composition being adjusted to a ph of 6 2 directions for use of the invention call for pouring it into a previously flushed cooling system and idling the engine for 30 minutes the cooling system is then flushed with water and recharged with an appropriate amount of antifreeze and water for the conditions under which the invention will be used it has been discovered that the only suitable non ionic surfactant is an octylphenoxypolyethoxyethanol non ionic surfactant having the formula str3.