Oil analysis is about surfacing problems that were otherwise hidden from view. We’ve all heard the phrase “if it ain’t broke don’t fix it,” but an important corollary is “if it is broke, fix it fast.” The basic problem with this strategy is not knowing when something is actually broken.
For many organizations, oil analysis offers an effective solution, but it works only if users are literate in its language and apply it effectively. While oil analysis is not a panacea for all machine reliability problems, it does offer many special opportunities. For one, the oil is typically the carrier of both the root cause and symptoms of impending failures.
Think about it . . . the oil has intimate contact with the machine’s most critical surfaces - some frictional, others not. And the oil goes places that no human, instrument or probe can go - often deep into the bowels of the machine. Nearly everything that becomes detached from a machine must plunge into the moving oil. One could say that all wear particles must spend at least some amount of time in the lubricant before coming to rest elsewhere (filters, sumps, etc.). And the smallest particles many never transfer out of the oil, offering an evolving chronology of the wear that is occurring.
But there is much more to oil analysis than monitoring failure. The oil carries other important messages that need attention and punctuation. If a machine’s operating conditions remain unchanged (speeds, loads, pressure, etc.), what other factors could be the source of failure? If you are following my train of thought, you are probably thinking about the oil itself, right? Indeed, the oil inflicts wounds on itself and on the machine it was designed to protect. While the oil carries away wear debris, it also carries infection and disease.
What could corrupt the quality of the oil to such extent that it could lead to film thickness decay, heat generation, abrasion, corrosion, cavitation or similar afflictions? The list is long. How it happens and when it happens varies considerably too, but the fact remains, the oil’s properties will change accordingly.
If the culprit in the oil is contamination (water, glycol, dirt, etc.) then we look for contamination in the analyses. If the culprit is the wrong or degraded oil, then we look for changes in physical and chemical properties in the analyses. If the culprit is a skipped oil change, we will see it in the analyses. Sounds simple doesn’t it? It generally is. There is only one critical thing that remains . . . actually doing it!