Used Oil Testing: Oil Condition Analysis

There are three basic categories of used oil analysis tests: Wear Metals, Contaminant Detection and Oil Condition, which is the subject of this blog post. Eurofins TestOil offers three primary tests for evaluating oil condition:  Fourier Transform Infrared Spectroscopy (FTIR), Viscosity, and Acid Number.

                Eurofins TestOil’s Matt McMahon, Oil Analyst III Field Technician, explains the details of each test.

  • FTIR: measures the amount of specific compounds related to the base stock of the lubricant.  Most importantly it indicates the level of oxidation byproducts present in mineral oils.
  • Viscosity measures the sample’s resistance to flow.
  • Acid Number measures the amount of acidic components in the oil sample.

                Matt points out that while these tests each provide their own information, running the tests together yields additional information. “As oils degrade, the amount of acidic components and oxidation increase,” he says. “Often, when antioxidants are depleted, acid levels increase exponentially. When acid number and FTIR oxidation levels increase, viscosity tends to increase as well.  This is an indication that the oil has reached the end of useful life and should be changed. If viscosity drops gradually, while oxidation and acid number results stay the same, this may indicate viscosity shear down. If viscosity drops suddenly, it’s often the result of the wrong product.”[1] 

                Unlike most competitors, if the viscosity detected in the initial analysis is outside the normal range or has deviated significantly from previous samples, Eurofins TestOil will automatically rerun the test to verify the result.   

                Matt recommends new oil sampling to monitor oil quality so that oil outside of specifications can be flagged before being placed into service. “Also, we can use the new oil results to populate the new oil column on the lab reports so that a side-by-side comparison can be done,” he explains. “Often this is useful when there are formulation changes in new oil deliveries that are different than what is currently in the machines. Without this information, changing levels may erroneously suggest contamination with another product.”  

                Matt concludes that having oil condition information is important when trying to diagnose possible machine wear problems as the lubricant condition could be a root cause for accelerated wear.

                This blog post is the second in a series on the 3 categories of oil tests. In addition to Oil Condition testing, the other 2 are:

  • Wear Metals testing that detects and measures the presence and volume of a range of potentially harmful elements in the fluid.
  • Contaminant Detection testing helps analysts identify foreign contaminants that may have entered the lubricating system.

For more information on working with Eurofins TestOil for oil analysis and training visit Contact: 216-251-2510;

About Eurofins TestOil

With more than 30 years of experience in the oil analysis industry, Eurofins TestOil focuses exclusively on assisting industrial facilities with reducing maintenance costs and avoiding unexpected downtime through oil and fuel analysis program implementation. As industry experts in diagnosing oil-related issues in equipment such as turbines, hydraulics, gearboxes, pumps, compressors and diesel generators, Eurofins TestOil provides customers with same-day turnaround on routine oil analysis testing.  For more information on partnering with Eurofins TestOil on oil analysis programs or training opportunities visit Contact: Michael Barrett 216-251-2510; 

About Eurofins – the global leader in bio-analysis

Eurofins is Testing for Life. Eurofins is the global leader in food, environment, pharmaceutical and cosmetic product testing, and in discovery pharmacology, forensics, advanced material sciences and agroscience Contract Research services. Eurofins is also a market leader in certain testing and laboratory services for genomics, and in the support of clinical studies, as well as in BioPharma Contract Development and Manufacturing. The Group also has a rapidly developing presence in highly specialised and molecular clinical diagnostic testing and in-vitro diagnostic products.

With over 61,000 staff across a network of 940 laboratories in 59 countries, Eurofins’ companies offer a portfolio of over 200,000 analytical methods. Eurofins Shares are listed on Euronext Paris Stock Exchange.

[1] During this process, also called Shear Thinning, the viscosity can be lowered by an entire ISO grade, leaving the equipment subject to accelerated wear and seizure.

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