Insolubles by Pentane Membrane Filtration

This method describes the measurement of pentane insolubles in used oils. The results are reported as % weight pentane insolubles at x microns (where x = pore size of filter used) or mg/100 mL. This test measures wear debris, dirt, products of combustion or leaking seals that are suspended in the oil and are insolubles in pentane, which can all lead to oil degradation. Samples are prepared by dissolving a specified weight in pentane and passing it through a membrane filter or by direct filtration of a specific volume of sample under vacuum. The insolubles are calculated from the weight of the debris remaining on the filter and the total weight or volume of the sample taken.