Don't shoot the messenger

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Oil analysis provides information about lubricant health, machine condition and the incidence of contaminant ingress. This powerful combination enables the maintenance professional to proactively manage the life of mechanical equipment and detect and analyze abnormal wear conditions so that they may be dealt with effectively and with limited impact on the organization.

I always have been surprised, and even a bit miffed, by the fact that most samples judged as non-conforming result in a knee-jerk reaction to change the oil . . . often without further consideration or analysis. Granted, an oil change is often necessary as part of an overall corrective action, but not always. By itself, an oil change is rarely the answer. 

Oil analysts from the steel industry recently reported that of all samples judged non-conforming, only 6 percent were identified as “other,” a category that includes lubricant degradation, while 74 percent were judged so as a result of high contamination and 20 percent were attributed to abnormal machine wear (see figure). Others report similar statistics. In one study, only 3.8 percent of samples judged non-conforming were due to lube degradation.

A simple oil change doesn’t usually solve your problem; it just sweeps it under the rug. While many perceive changing the oil in response to non-conforming oil analysis results as an “easy fix,” it is more often than not analogous to shooting the messenger. I believe the “shoot the messenger” approach to oil analysis creates three serious risks to equipment reliability.

1) It turns a deaf ear to abnormal machine wear. When a machine is overloaded, stressed by unhealthy conditions or simply reaches the end of its fatigue life, it tells us by communicating in various ways. Among the most sensitive ways is through the oil.

Wearing surfaces deposit wear particles in the oil. Oil analysis enables us to communicate with the machine, at least unilaterally — it talks and we listen. If we decode the message, the machine reveals which component is at risk, the root cause of the problem and the severity of the situation. In some cases, we can remove the forcing function that causes wear and avoid failure. In other cases, we can schedule the corrective action. In either case, we reduce the event’s impact on the organization.

Simply changing the oil in response to abnormal wear on an oil analysis report is like hanging up on your machine after it called you on the phone to tell you it’s sick.

2) It turns a blind eye to contamination. Particles, water, acid, coolant and fuel are among the contaminants that rob life from your machine and promote oil degradation. Responding effectively to lubricant contamination is akin to controlling cholesterol. While a high cholesterol level doesn’t suggest the individual is having a heart attack, it does increase the risk of developing heart disease. Controlling cholesterol is a proactive measure that reduces the likelihood of heart disease. Controlling lubricant contamination is a proactive measure that increases machine life.

Ignoring these opportunities to extend machine life through contamination control efforts leaves a serious amount of money on the table that otherwise would show up on the bottom line.

3)It misses improvement opportunities. Even in instances where the oil is degraded, you may extend the degradation cycle, often substantially, by selecting another product or controlling heat or aeration levels. A minor change in response to oil analysis could significantly extend oil life and reduce maintenance costs.

Drew Troyer is the senior editor of Machinery Lubrication Magazine. If you have a lubrication or oil analysis question, contact Coach Troyer at or e-mail .

This article appeared in the June/July 2002 issue of MRO Today magazine. Copyright, 2002.

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