Abstract
Used and unused lubricating oils were characterized in terms of their additives. The analysis was both physical and chemical in nature. Physical parameters included pour point, flash point, specific gravity, percentage sulfated ash and color of the samples. A decrease in all these values was observed for all used samples. Chemical tests included the estimation of chloride and zinc. Besides this, the other possible groups such as thiosulfates, olefin copolymers, esters and phthalates were characterized by IR spectroscopy.