INSOLUBLES IN USED LUBRICATING OILS BY PAPER FILTERATION (LMOA METHOD): ASTM D7317
EXPLANATION
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. A significant change in the amount of coagulated pentane insolubles indicates a change in oil, and this could lead to lubrication system problems. Coagulated pentane insolubles measurements can also assist in evaluating the performance characteristics of a used oil or in determining the cause of equipment failure.
This test method was originally developed by Locomotive Maintenance Officers' Association (LMOA). This test method, in general, does not correlate with Test Method ASTM D893 on insolubles in lubricating oils, since it uses separation by centrifugation and a more concentrated solution of anti-coagulant. The correlation between this test method and enhanced thermal gravimetric analysis procedure in Test Method ASTM D5967 has not been investigated.
TEST SUMMARY
A 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.
TEST PRECISION
Repeatability: 0.061 X + 1.77
Reproducibility: 0.237 X + 1.77
where X is the average of two results.
The procedure ion this test method has no bias because results can only be defined in terms of this test method.
