A New Test Method for Insolubles in Used Lubricating Oils

Abstract

The ASTM method has been commonly used, as a standard determination method for the insolubles in used oils. But, a defect of this method is that a part of the coagulant remain in insolubles, and it is difficult to determine insolubles in used oil which contains some type of polymeric detergent. In order to determine insolubles in such used oils, we propose a new method by which insolubles are extracted with a cylindrical filter paper dipped in a mixture of heptane and coagulant prior to use. Some experimental results are described and the best operating conditions examined. Conparison was made between the new and the other methods.