Abstract: A cleaner-inhibitor and method of incorporating same into an automotive or diesel coolant system consisting of 2-4 fluid ounces per gallon of a cleaner whose basic components are:A. an aminopolycarboxylic acidB. an .alpha. hydroxy acid such as gluconic, tartaric, or citricC. an azole copper protector such as mercaptobenzothiazole (MBT) and a monoaryl triazole such as benzotriazole or tolyltriazoleWherein the ratio of A:B:C is about 3:1:1 to 2:1:1.A, b, and C above constitute a Deposit Release Agent in the cleaner.The cleaner above is combined with an inhibitor which is a multi-component inhibiting composition of the boron-nitrite type containing an alkali metal silicate and which may include a copper inhibitor and a polymeric dispersant, which is a water-soluble carboxylic acid polymer such as styrene maleic anhydride copolymer, a polyacrylate or methacrylate copolymer or carboxymethyl cellulose.The cleaner-inhibitor is adjusted with caustic to give a pH in the range 7.5-12.6 and preferably 7.5-10.

Abstract: A cleaner to be used preferably in conjunction with conventional glycol-type collants in automotive cooling systems and methods of using same. The present cleaners may be referred to as extended-life cleaners which may be added to the glycol coolant and are co-extensive with the life of said glycol. These cleaners operate to dissolve deposits, minimize corrosion damage, and dissolve organic degradation products, all of which cause heat transfer difficulties. The basic cleaner comprises:A. an aminopolycarboxylic acidB. an .alpha. hydroxy acid such as gluconic, tartaric, or citricC. an azole copper protector such as mercaptobenzothiazole (MBT) and a monoaryl triazole such as benzotriazole or tolyltriazoleWherein the above components are combined in a weight ratio ranging from 3:1:1 to 2:1:1.