This paper reviews the use of test strips for measuring the composition of engine coolants. The tests described include test strips for freezepoint, cylinder lining cavitation corrosion protection, reserve alkalinity, pH, chloride, and mercaptobenzothiazole.
Freezepoint strips work with reasonable accuracy with both ethylene glycol and propylene gly col based coolants. They will also work with mixtures of the two. The strips are shown to work with coolants containing phosphates, borates, or benzoates. Data show that good results can be obtained with new users so that training is minimized.
Strips for liner cavitation protection are described. Good results were obtained with visually read strips for nitrite in the range of 200 to 4000 ppm and for molybdate in the range of 75 to 1500 ppm. A hand-held reflectance meter to read these strips is described. Precision and accuracy data are given. The strips are not sensitive to glycol concentration.
Data are presented for the accuracy of test strips for reserve alkalinity and pH. Test strips for mercaptobenzothiazole are described. A description is also provided of a prototype test for chloride levels in used coolants where the makeup water may have contained salts. In all cases, test strips were found to be accurate, easy-to-use, inexpensive devices useful for routine field monitoring of coolants.