Oil analysis is a very beneficial diagnostic “tool.” Establishing a history of wear patterns (trendline) is the most reliable and accurate method of interpreting oil sample test results. It’s a fact that two identical engines, working under identical conditions, can generate wear particles at different rates. But prior to establishing a trendline, the lab technician can still compare the oil sample results to the wear limit tables for a general idea of how the internal components are wearing.
Available at additional charge, oil analysis is highly recommended, even if hours on oil are low. If you elect to include oil analysis as recommended, oil samples of engines, transmissions, and generator(s) will be taken. Oil samples are then sent same day via FedEx for morning delivery to CAT oil lab. Excluding weekends, oil sample results are usually available within 48 to 72 hours. In addition to oil lab’s analysis, On-Site Diesel will also provide interpretation of results.
To check internal cylinder condition, borescope inspection service is available. If engine crankcase pressure is high and/or engine oil sample(s) contain abnormal levels of chrome (piston rings), aluminum (pistons), and iron (cylinders), a borescope inspection may be recommended.
Cylinder Leak Down Test
To check cylinders for compression loss, cylinder leak down test is available. By using a regulator, 80 PSI of air pressure is injected into the cylinder being tested. With the piston at top dead center and the valves closed, pressure readings between 60 and 80 PSI are acceptable.
If a cylinder pressure is less than 60 PSI, oil is added to the cylinder and the test is repeated. An increase in the pressure reading with the addition of oil indicates a problem with the piston rings. No change in the pressure reading after the addition of oil indicates a problem with the valves or both valves and rings. Note: Cylinder leak down test is only available on certain CAT® engine models.