Efficient fleet operation is aided by planned preventive maintenance. An integral part of that process should be monitoring component wear through 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 lowering total operating costs.”
Diagnostic oil analysis alerts maintenance personnel to potential hidden or emerging 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.”
Virtually all oils used in equipment can be tested, but the majority of tests are engine oil samples, followed by transmission, driveline or gear applications and hydraulics, notes Mark Betner, heavy duty product manager, Citgo Lubricants.
Regular sampling and analysis of these fluids establishes a baseline of normal wear and can help indicate when abnormal wear or contamination is occurring. To ensure consistent results, Arcy recommends taking samples in the same manner each time. For example, he notes, “Withdrawing [engine] 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 accompanying each sample should be as complete as possible. This information is critical to provide a complete and accurate analysis report. Be sure to note if any oil was added between oil drains and the type used.
Once a lab receives an oil sample, it typically takes 24 to 72 hours before the data is ready for reporting. For optimal benefit, samples should be sent in promptly after they are taken.
“It is very important that the oil analysis user realizes the longer it takes to get the sample to the lab, the longer it takes to get data back,” Betner comments. “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.”
Metallic trace particles from wear, products of the combustion process and any externally generated contaminants will all become trapped in oil as it circulates through the engine or other operating systems. Consequently, the oil becomes a working history of these components.
By identifying and measuring these impurities, you can get an indication of wear rates and any excessive contamination. “Used oil samples can tell you if contaminants such as water, coolant, fuel or dirt are getting into the oil, indicating a head gasket leak, leaking fuel injector or other problems,” says Arcy. “Spectrochemical analysis detects the presence of wear metals in the oil. Unusually high amounts 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.
Using computerized test equipment, typically a very small amount of used oil sample is energized (burned in an electric arc), explains Jeff Wohlwend with OilCheckUp, a custom manufacturer and 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.