On-Site Analysis makes diagnostic testing equipment to help take the guesswork out of tinkering under the hood. The company's MotorCheck analyzer is a mechanical "blood test" that analyzes used oil to test for the presence of metal debris, coolant, or water. Another product, FuelCheck, analyzes both gasoline and diesel for qualities that affect engine performance. Other products include MetalCheck (engine test for the presence and quantity of wear metals) and TruckCheck (for large trucks). On-Site's customers include truck stops, quick-lube centers, and automotive repair shops, as well as automotive manufacturers.