EXPLANATION
Pentane insolubles above 0.8 μm in size may lead to increased wear that can lead to premature equipment failure in critical applications. This test method covers the determination of pentane insolubles for particles exceeding 0.8 μm in new and used lubricating oils. Particles sizes above or below this limit can also be studied with appropriate size membrane filters; however, precision for such sizes is not known.
TEST SUMMARY
A sample of oil is mixed with pentane in a volumetric flask, and the oil solution is filtered through an 0.8 μm membrane filter. The flask, funnel, and the filter are washed with pentane to effect a complete transfer of particulates onto the filter. The filter with particulates is dried and weighed to give the pentane insolubles.
TEST PRECISION
Where X is the average of two results.
The reproducibility of this test is very poor, and this test method is unsuitable for comparison of interlaboratory results.
The bias of this test method has not been determined.