Understanding the S·O·S Oil Analysis Tests
Know what the numbers mean and maximize your investment
S·O·S oil analysis is a valuable management tool that can maximize equipment life and productivity, and minimize operating costs and downtime. Four types of analysis are performed on engine, hydraulics and drivetrain oil. • Wear Rate monitors and tracks metal wearparticles, contaminants and oil additive package elements • Oil Condition compares used oil to new oil to see if it is providing adequate lubrication and protection • Oil Cleanliness determines if abrasive contaminants are causing accelerated wear • Additional Tests detect water, glycol or fuel in oil Take oil samples at consistent intervals to detect potential problems early, reduce repair costs andlessen the impact of downtime.
You’ll get greater benefits from your S·O·S oil analysis program when you understand the tests chosen by Caterpillar® engineers to monitor oil condition and contaminants.
S·O·S Wear Rate Analysis
Prevent problems and reduce costs by knowing wear rates
Wear Rate Analysis is an integral part of our S·O·S program that helps you maintain equipment performanceand maximize availability. Through regularly scheduled testing of oil samples from your engine, hydraulics and powertrain systems, Wear Rate Analysis detects tiny metal particles caused by component wear. By monitoring trends in the type and quantity of particles, you can get early warning of problems before major damage occurs.
Understanding wear metals
Every oil-washed system—engines,hydraulics, transmissions, and final drives— produces wear metals in everyday operation. If wear accelerates, the concentration of wear metal particles increases, signaling a problem. Wear Rate Analysis allows you to find problems before they result in major repairs or machine failure. Wear Rate Analysis can detect particles that range up to about 10 microns in size. Wear metal concentrations areexpressed in partsper-million (or ppm). The S·O·S oil analysis program tests for at least nine different substances: copper, iron, chromium, lead, tin, aluminum, molybdenum, silicon and sodium. All are wear metals found in Caterpillar machines and engines except silicon (which generally indicates dirt) and sodium (which indicates water or coolant). Certain elements in a sample may be from the oiladditive package rather than from wear within the system. Skilled dealer interpreters can tell the difference between normal elements and those that indicate abnormal wear.
Trending wear metals in your equipment
Two identical machines under identical conditions may generate wear particles at different rates. Our S·O·S interpreters have access to a large database of samples for comparison with samplesfrom your equipment. However, your own machines provide the best guidelines for appropriate levels of wear metals in each compartment. That’s why trending is an essential part of Wear Rate Analysis. After three samples have been taken from a particular compartment, a trend for each wear metal is established. Our interpreters then compare subsequent samples to this trend line to quickly spotdeviations as well as monitor gradual changes in concentration levels. This attention to trends also assists with life cycle analysis, helping you optimize productivity.
The technology behind Wear Rate Analysis
We use an emission spectrometer to perform Wear Rate Analysis. The spectrometer determines wear elements and silicon in a sample by subjecting the oil to very high temperatures. At thesetemperatures, the elements in the sample are “atomized,” with each emitting a different wavelength of light energy. An optical system measures and records the light energy and calculates the results in parts-per-million for each element.
Combinations of Classic Wear Elements
Silicon (dirt) Iron Chrome Iron