Infrared absorptions of TLC subtractions of used motor oil, original oil, base oil and the additive, indicate the transformation of the polar and nonpolar components by further oxidation and oxidative degradation of carbonyl compounds into acids, esters and peroxides. Organic nitrates and nitro compounds were also detected after 2000Km and 3000Km service. The effects of basic calcium sulfonate additives, starting with used oil l000Km, 2000Km, 3000Km service, vacuum distillates of used oils and base oil, were studied. It has been found that the dispersant properties of these sulfonates are profoundly influenced by their structure. The alkalinity of the calcium sulfonate additive was determined by spectroscopic-IR method.