TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Fluid: The fluid comprises (wt.%): hydroxylated carboxylic acid (0.01-10, preferably 0.1-5); and further comprises alcohol (0.1-99.9) and/or water (0.1-90); a corrosion inhibitor comprising azole, siloxane, colloidal silica, silicate, 6-14C aliphatic or aromatic mono- or di-carboxylic acid, 6-14C aliphatic or aromatic mono- or di-carboxylate, tall oil fatty acid, borate, nitrate, nitrite or their alkali metal salt, alkaline earth metal salt, ammonium salt or amine salt; an oxy-anion of molybdenum, tungsten, vanadium, phosphorus and/or antimony; and a colorant, antifoam agent, wetting agent, biocide, bitterant and/or dispersant. Preferred Package: The package comprises hydroxylated carboxylic acid (1-100 wt.%); a corrosion inhibitor (1-99 wt.%); and a solvent (0.5-50 wt.%). Preferred Components: The hydroxylated carboxylic acid (I) is of formula R2(R4(H)x(COOH)y-z)(R3(COOH)z) (II) (preferably compounds of formulae (V), (VI) or (XI)); or is a compound of formula (X). The ester of the carboxylic acid is of formula (OH)x(R1)(COOH)y-p(COOR8)p. The salt of hydroxylated carboxylic acid is of formula (OH)x-q(OM)q(R1)(COOH)y-p(COOM)p. The alcohol comprises a monohydric alcohol and/or a polyhydric alcohol (preferably methanol, ethanol, propanol, butanol, furfurol, tetrahydrofurfurol, ethoxylated furfurol, alkoxy alkanol, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, butylene glycol, glycerol, glycerol-1,2-dimethyl ether, glycerol-1,3 dimethyl ether, monoethylether of glycerol, sorbitol, 1,2,6-hexanetriol and/or trimethylol propane).m and n=0-15 (preferably 0-10);v=2,4,6,8 or 10;p=1-9;R8=group of formula -(CH2-CH2-O-)s-CH2-CH2-OH;s=0-10;q=1-9;M=organic cation or inorganic cation (preferably alkali metal cation, alkaline earth metal cation, transition metal cation, ammonium cation, phosphonium cation, pyridinium cation, imidazolinium cation, pyrazolinium cation, triazolinium cation, and/or tetrazolinium cation);andT1=-C(=O)-O-C(=O)-.Provided that(1) sum of m and n is less than or equal to 16;(2) v or p is less than or equal to y; and(3) q is less than or equal to x. EXAMPLE - A coolant concentrate comprising (wt.%): 2-ethyl hexanoic acid (2-3), neodecanoic acid (0.5-1), sodium tolytriazole (0.2), polypropylene glycol antifoam (0.2), and OCD-448 (RTM: maleated fatty acid hydroxylated by hydrogen peroxide or OH radicals generated by the reduction of oxygen on the metal coupon surfaces) (0.4), sodium hydroxide (adjust the pH to 8.7), and ethylene glycol (balance) were prepared. A fluid (control) was prepared by heating solution (500 ml) of coolant (50 vol.%) and de-ionized water (50 vol.%) in a glass beaker at 103 degrees C for 2 hours while aerated by air bubbling. A test fluid was similarly prepared by using the condition for control except that multiple metal coupons specified by ASTM D1384 were in the beaker and the beaker was heated for 5 hours. The test/control fluid showed a foam volume of 12/21.