With the cooperation of major engine manufacturers, oil companies and additive suppliers, Analysts, Inc. has developed a technology that quickly, accurately and economically measures and helps monitor the amount of soot buildup within diesel engines.

Called LEM®—short for Light Extinction Measurement®—this new technology identifies levels of soot within an engine’s lubricant. Through the program's reporting procedures, LEM helps you monitor soot levels to avoid the harmful effects that it will cause.

Results and analysis of new laboratory procedures on your used oil samples will accurately measure the amount of soot that may be present within your engines.

That amount is then applied to OEM-recommended maximums for particular engines. The procedure is done by directly reading your oil sample; the sample is not altered through dilution or burning.

LEM overcomes the drawbacks of other laboratory methods to determine a lubricant’s remaining service range. It is accurate for new engine technologies, lubricants and today's fuels.

LEM accommodates higher levels of soot that are produced in some engines. It is inexpensive. It is fast. And it is easy to understand.

Before LEM, three laboratory methods could give indications of soot content. Those methods have obvious drawbacks with the new standards and the need to monitor this harmful by-product.

  • Infrared (IR) testing may have been acceptable for past emission levels. However, future soot levels in diesel engine lubricants will routinely exceed IR’s capacities and capabilities. IR results are erratic.
  • Thermogravimetic Analysis (TGA) tests are time-consuming and expensive. The need to regularly monitor soot can make this type of analysis out of reach for many truck and fleet owners.
  • Total Solids determines the total content of contaminants in oil. It does not definitively measure soot. Instead, it measures the combined amount of contaminants, including dirt, wear metals, and even additives. Additionally, this testing uses solvent/extraction, which is an environmental concern and increases costs even more because of waste disposal expenses.

LEM combines the speed of IR with the accuracy of TGA. It gives you the key data for determining the most effective and economic oil change intervals for the engines within your fleet.

LEM helps you improve fleet management and prolong the service of your engines by helping you:

  • Avoid harmful engine deposits
  • Maximize the service of your lubricants
  • Maximize engine performance
  • Determine optimum oil change intervals

LEM readings:

  • Correlate almost point-for-point with soot mass percentages as determined by expensive TGA measurements—even when high soot concentrations are present.
  • Give no false positive high soot readings that are caused by conditions unrelated to fuel soot, unlike IR testing.
  • Require no solvents, standards or reference oils. The procedure reads directly from your oil sample.

Once the LEM Analyzer has scanned the sample, Analysts’ high speed LEM computer program examines the results and automatically calculates the percent soot.

To learn more, download a portable document file (pdf) on Analysts' LEM Analysis program. You can print from the file in black-and-white or color. The file is 140 KB and is two pages.

You must have Adobe Acrobat Reader enabled on your system as a plug-in to your browser. A free copy can be obtained from www.adobe.com.

Or, you can request this 2-sided, full color sheet by contacting Analysts, Inc..