Patent ID: 8066902

Claim:
A corrosion inhibiting coolant for inhibiting corrosion in brazed aluminum surfaces comprising residual flux agent, said coolant comprising: 10% to 99% by weight of a freezing point depressant; and an acid functional corrosion inhibiting component comprising a brazed metal corrosion inhibitor comprising a polycarboxylic acid functional compound having the structure: wherein R 1 , R 2 , and R 4 are each independently selected from the group consisting of H, OH, COOH, C 1 -C 10 alkyl groups, glycol esters, anhydride groups, COOM, and combinations thereof, wherein M is at least one of alkali metal ions, alkali earth metal ions, NH4 + , amines, imidazoline, polyalcohol esters, C1 to C12 alkyl groups, and combinations thereof; wherein R 3 is H or COOH with the proviso that: at least two of R 1 , R 2 , and R 4 contain an anhydride group, and at least one of R 1 , R 2 , and R 4 contain the group —COOM, wherein M is defined above.