ASTM D7317 Standard Test Method for Coagulated Pentane Insolubles in Used Lubricating Oils by Paper Filtration (LMOA Method)
4. Summary of Test Method
4.1 A representative sample of used lubricating oil is mixed with pentane-coagulant solution and filtered under vacuum. The filter is washed with pentane, dried, and weighed to give coagulated pentane insolubles.
5. Significance and Use
5.1 Coagulated pentane insolubles can include oil-insoluble materials, some oil-insoluble resinous matter originating from oil or additive degradation, soot from incomplete diesel fuel combustion, or a combination of all three.
5.2 A significant change in coagulated pentane insolubles indicates a change in oil, and this could lead to lubrication system problems.
5.3 Coagulated pentane insolubles measurements can also assist in evaluating the performance characteristics of a used oil or in determining the cause of equipment failure.
5.4 High values of coagulated pentane insolubles have been associated with plugged oil filters, leading to opening of the bypass valve and circulation ofunfiltered oil in the engine. This can lead to increased piston deposits, increased bearing wear, and premature engine failure.
