How to interpret an oil analysis report

Oil analysis programs can save your business money. Regular testing of your oils and lubricants is an integral part of a proactive maintenance program that will help you identify contamination issues, reduce product waste and avoid costly equipment breakdowns and repairs. We are happy to provide our customers with this service through the Chevron LubeWatch Oil Analysis program and by working with Polaris Laboratories. Our customers have seen the results of enrolling in this program for their business.

If you’ve decided it’s time to start an oil analysis program at your company, that’s great. Getting started will take time to determine the best set up for your equipment and maintenance needs. We’ll help you determine a schedule for regular sampling and testing. Then you’ll receive a report full of recommendations for your business.
Understanding your oil analysis report is difficult. Nearly 32% of lubrication professionals do not know how to interpret an oil analysis report from a commercial laboratory, according to a recent poll from That’s a little disconcerting. If you’re going to invest in oil analysis, understanding your reports is crucial. Luckily we are here to help.

First, you need to understand what type of testing your samples will undergo. The most common parameters tested are:

  • Viscosity: Measuring the viscosity of your oil and lubricants is one of the first things you may notice in your report. Every lubricant is classified at a particular ISO viscosity grade (VG) to function correctly. If that reading has changed, your lubricant may cause overheating, wear and equipment breakdowns. If your results show that the viscosity grade of your lubricant has fallen within plus or minus 20% of the original grade, the lubricant will not work correctly.
  • Acid Number/Base Number: If you’ve forgotten high school chemistry, here’s a quick reminder. An acid is a substance that forms hydrogen ions. It’s corrosive and has a low ph value like vinegar. A base substance gives away hydrogen ions in solutions, and reacts with acids, like ammonia. In your oil analysis report, an acid number reading and base number reading indicate the level of acidic or basic properties the substance has. An acid number that is too high or low may indicate oil oxidation, an incorrect lubricant or additive depletion. Similarly, a base number that is too high or oil may indicate the presence of fuel, soot, the use of the wrong lubricant, leakage or oil oxidation. Both of these numbers can help pinpoint potential contamination issues or incorrect lubrication use.
  • Elemental analysis: Contamination issues are the reason many companies choose to pursue an oil analysis program. This testing checks for the presence of wear metals, contaminants or additive elements in the oil. Some of the tests performed may include Rotating Disc Electrode (RDE) and Inductively Coupled Plasma (ICP). These tests determine particle size, which is compared to previous tests to determine if contamination is occurring. Particle Counting is another test that accounts for the size and quantity of particles in the oil. There are several different methods to perform this test.
  • Moisture Analysis: Using a test known as the Karl Fischer titration test, moisture analysis measures any water present in three different forms: dissolved, emulsified and free. Results from this test help determine if there are potential leaks that may be contaminating your oil, internal condensation, temperature issues or seal leaks.

Now that you know what may be tested, it’s time to understand how it may look on your report. Each lab has a unique method of creating their reports, but universal principles remain. Most reports are broken down into sections such as these:

  • Information section: Your information, equipment information and type of lubricant being tested. This section is crucial and should always be checked first. It determines where the sample was pulled from, so if there are any issues, you know where to look.
  • Testing sections: These sections break down the variety of tests that were performed on the sample and the results. These tests are compared to previous results.
  • Results section: This portion of the report breaks down the overall results of your test. These results may be compared to the previous testing that was performed.
  • Recommendations section: Based on the findings of your testing, the lab will provide written instructions for how to best use the results of your analysis. This section is where the value of your oil analysis program becomes visible. Using these results, you can pinpoint potential maintenance issues before they become a significant problem.

If you are having trouble understanding your results and how to implement your recommendations, let us help. We are here to make sure that you get the best value out of the oil analysis program for your equipment. An oil analysis program is a significant investment. Still, it can pay off quickly for your business if you follow a careful monitoring schedule and the recommendations outlined in your report. Sign up for our oil analysis program today.