Used Oil Analysis

Oil analysis is an effective tool that can help you monitor the condition of your engine,” says Dan Arcy, OEM technical manager, Shell Lubricants. “The knowledge gained from a consistent oil analysis program can assist you in optimizing your oil drain interval, help increase equipment reliability, minimize unscheduled downtime and more precisely track operating efficiency and maintenance practices.

“The combination of all this contributes to helping lower total operating costs.”

Diagnostic oil analysis alerts maintenance personnel to hidden or emerging potential problems or failures, says Will Willis, Jr., president and CEO, On-Site Analysis, a company that offers technologies that interpret sophisticated technical measurements into simple-to-understand diagnostic statements.

“That means you can do preventive maintenance repairs while they’re small, rather than wait for costly catastrophic failures,” he says. “Less failure translates to fewer tows and breakdowns and less vehicle downtime, and that generates improved vehicle uptime.”


There are a number of reasons for, and benefits to be had, from used oil analysis, Mark Betner, heavy duty product manager, Citgo Lubricants says. Among them:

  • Verify when to change oil – “One of the more frequently asked questions is: What is the right time to change oil or how far can equipment go on any oil?” he says. “This question requires an understanding of engine manufacturer recommendations, but oil analysis can also provide insight as to what factors impact oil change intervals.”
  • Engine warranty protection – Oil analysis can provide support in the event of a warranty dispute, says Betner. “Knowing oil condition history provides additional input as to what has been happening with oil, and to some extent, engine wear related problems.”
  • Increased resale value – Some oil analysis programs, like Citgo’s LubeAlert, have a data summary analysis feature that gives a detailed oil analysis history on a vehicle. The information “provides a prospective buyer with valuable information as to how the vehicle was maintained and the wear history of the engine, adding potential resale value to the vehicle,” he says.
  • Preventative maintenance tool – Successful users of oil analysis “will testify to the fact that oil analysis has saved costly downtime and engine repairs because they are aware of developing problems.” When oil contaminations reach critical levels, premature catastrophic engine failures can result.
  • Oil quality evaluation – Most lubricant manufacturers offer different quality levels. “If used correctly and consistently, oil analysis can provide oil condition trends that reflect the superior performance capability of an oil,” says Betner.


Oil analysis involves sampling and analyzing oil for various properties and materials to monitor wear and contamination in an engine. Sampling and analyzing on a regular basis establishes a baseline of normal wear and can help indicate when abnormal wear or contamination is occurring.

Simply put, oil that has been inside any engine or moving mechanical apparatus for a period of time reflects the possible condition of that assembly. Oil is in contact with the mechanical components as wear metallic trace particles enter the oil. These particles are so small they remain in suspension.

Products of the combustion process of an engine will also become trapped in the circulating oil. Any externally caused contamination also enters the oil.

Consequently, the oil becomes a working history of the engine or mechanical apparatus. By identifying and measuring these impurities, one can get an indication of the rate of wear and of any excessive contamination.

Virtually all oils used for automotive equipment can be tested, but the majority of tests are engine oil samples, followed by transmission, driveline or gear applications and hydraulics, says Citgo Lubricants’ Betner. The tests performed will differ depending on the fluid, adds Arcy of Shell Lubricants, and the analysis program should also be tailored for the type of fluid.


Oil analysis serves as an early warning system that can alert a maintenance operation to problems before they become costly headaches, says Shell Lubricants’ Arcy. “Used-oil samples can tell if contaminants – such as water, coolant, fuel or dirt – are getting into the oil, indicating a head gasket leak, a leaking fuel injector or other problems.

“Spectrochemical analysis detects the presence of wear metals in the oil. Unusually high amounts of wear metals could be a sign of abnormal wear.”

Spectrochemical analysis is an analytical technique in which an oil sample is heated to a high temperature, usually in a carbon arc, to produce emission lines whose intensities are proportional to the abundance of elements present.

Typically with spectrochemical analysis, using computerized test equipment, a very small amount of used oil sample is energized (burned in an electric arc), explains Jeff Wohlwend with OilCheckUp, a custom manufacturer and worldwide distributor of filtration test media and multi-fluid test strips. This results in a wavelength, or color, of light that is compared against the standard acceptable levels of wear metals or contaminants. These results reflect the concentration of all dissolved wear metals, both from the component and the fluid.

This lab analysis provides a quantitative evaluation of a fluid’s composition and condition, including viscosity, total sludge content, particle count, glycol contamination, fuel dilution, fuel-soot level, grime and additive package depletion, adds Ron McElroy, president and chief technology officer of Fluid Rx, a company that does instant lubricant diagnostics.

Both Arcy and Citgo Lubricants’ Betner note that more specialized tests can be performed on an oil sample. There are oil analysis services that offer upgrades or additional testing depending on the application, operating conditions and maintenance goals, says Betner. Additional tests, or premium used oil analysis, can help in determining the optimum oil drain intervals or identify specific problems, Arcy adds.


When taking an oil sample, Arcy of Shell Lubricants advises taking a sample in the same manner each time, as this keep the results consistent. “Withdrawing oil through the dipstick opening is a good way to take the sample. This can reduce the chance of outside dirt or contaminants getting into the sample.”

All paperwork that accompanies each sample needs to be as complete as possible, says Betner of Citgo Lubricants. This information is critical to providing a complete and accurate analysis report.

Be sure to note if any oil was added between oil drains and what type was used, Arcy says.

Once a lab receives an oil sample, it typically takes 24 to 72 hours before the data is ready for reporting.

“It is very important the oil analysis user realizes that the longer it takes to get the sample to the lab the longer it takes to get data back,” Betner stresses. “It is not uncommon for samples to sit around shops waiting to accumulate several samples so that a bundle can be shipped to save on shipping costs. But in the long run, the value of the testing is lost due to this type of delay.”


When the oil analysis is received, it is necessary that the report be fully understood, says Citgo Lubricants’ Betner. Consult with the oil analysis provider if unsure of anything.

“Newer engines tend to have some anomalies that can produce false critical reports,” he says. “Knowing when and why these situations occur can avoid loss of confidence in the reporting, and more importantly, when and how to react to the data.

“Generally, oil contamination is the number one cause of lubrication-related failures, so critical reports involving coolant, dirt, fuel and in some cases, soot contamination, should get the full attention of the user.”

If the sample indicated a critical issue, the customer is contacted by phone or fax by the laboratory, communicating the sample result, Shell Lubricants’ Arcy says.


Oil and lubricant analysis programs differ in many aspects, including tests available, interpretations and reports, turnaround time, price and more. Consequently, adequate time and effort needs to be invested in order to choose the program that best serves your requirements and needs.

Citgo’s LubeAlert Oil Analysis Program, by way of example, is an electronic oil analysis program for heavy duty oils, gas engine oils and special products, including water-based hydraulic fluids. It manages more than 160,000 engines and more than 1,700 fleets, with all makes and models and a vast database documenting trends on virtually all types of diesel engines.

The program can also customize tests for oils not falling into standard categories.

The Summary Analysis feature of the LubeAlert Oil Analysis Program creates a “maintenance report card” that allows management to rate maintenance facilities, target problem areas and evaluate engine makes and models.

Late last year, Shell Lubricants revamped its Shell LubeAnalyst oil analysis program to better help customers improve equipment and vehicle reliability, while reducing maintenance costs. The program provides an online user interface that offers a worldwide sample historic database and failure trends on various types of equipment and engine types.

Reports show results from previous tests, graphs on oil properties, wear and contamination. Comments about any possible trouble areas and any recommended actions that may need to be taken are also provided.

The Shell LubeAnalyst program offers easy-to-use software enabling users to view results, track test results and view offline management information.


An inconvenience of lab analysis is the duration between sampling cycles and the turnaround between sampling and processing before the results are available to the shop for evaluation, observes Fluid Rx’s McElroy.

“For instance, glycol contamination and/or fuel dilution, which are two of the main killers of diesel engines, can begin to manifest shortly after sampling cycles,” he says. “Component damage or catastrophic failure may occur before the next sampling cycle and lab analysis is performed.

“Instant lubricant diagnostics is the stopgap between lab analysis cycles to catch these problems and prevent costly repairs and equipment downtime.”

Compared to the lab process, instant analysis offers a low-cost, quick and simple-to-understand method for determining a fluid’s condition at regular intervals on the spot, says OilCheckUp’s Wohlwend.

Instant analysis kits are simple to use, and no tools or special knowledge is needed. Simply follow the instructions included with each kit, says McElroy:

Willis of On-Site Analysis points out that with immediate results:

  • Test results are available while vehicles are in the shop so corrective action can be determined and necessary repairs addressed.
  • Service bay through-put is improved by speeding up the diagnostic phase of the repair service.
  • Vehicles are not taking up yard space while waiting for test results.
  • Scheduling of repairs can be planned before they become critical.
  • There is no loss of urgency due to lack of information.


All modern lubricants contain additives that inhibit breakdown, explains McElroy of Fluid Rx. As these additives are depleted, sludge forms. Instant analysis kits utilize a chromatographic process to provide a measure of additive depletion and the level of sludge or debris in a lubricant.

The chromatography technique indicates the total amount of wear metals and particle contaminants based on particle size (micron rating) with visual and comparative results to a new fluid sample of a preferred brand, Wohlwend of OilCheckUp says.

According to the two officials, the process basically works as follows: A drop of the sample oil or lubricant is placed on a thin layer of absorbent filter paper or specialized media. As the fluid test specimen percolates through the paper/media, bands and/or zones of different colors, densities and even unwanted wear metals and debris, form a chromatogram – a series of color bands or color graph.

Changes in the appearance of the zones or bands are a clear indication that something in the lubricant has changed. A closer look at the zones, their unique formation and the debris fields contained therein may indicate an increased level of contaminants, additive depletion, breakdown of fluid, viscosity changes, etc.

The instant analysis chromatography technique is not limited to any type of fluid, notes Wohlwend.

It can handle brake fluids, power steering fluid, automatic and manual transmission fluids, gear oils, crankcase oil, synthetic and petroleum-based fluids and oils alike, says McElroy. There is even technology that provides diagnostics for all formulations of antifreeze and coolants.