Diesel and Automotive Oil Analysis

All oil lubricated systems will have metal contamination after use. The best part about this is we can determine what metals and how much are present. The relationships of the different metals tell us where they are originating from and at what rate. Looking at the trend of this data over time lets you know if there is something in the engine that is not operating correctly. Caught early this can decrease the cost of maintenance significantly. See below for a standard table of these relationships.

All oils are blended to have a specific resistance to flow that is measured in a value called Centistokes. Each SAE grade of oil has a specific range that is necessary for that oil to be classified as a SAE weight of oil. As oils are used there are chemical and physical processes that will alter the oils viscosity. These include thermally loading the oil, fuel bypassing the pistons and entering the oil system (fuel dilution), or other physical processes. Each engine manufacturer specifies a specific grade of oil based on the physical needs of the motor. If the oil is below or above the needed viscosity you will see premature wear of the internal engine components. Below is a table of the SAE viscosity ranges.

Excessive fuel in the cylinder will create the conditions where the fuel is able to bypass the piston rings and enter the oil system. This has a net effect of diluting the oil and changing the lubrication characteristics of the oil. If left unchecked the engine will begin to increase the rate of wear metal production, and it can lead to premature failure of the motor.

Glycol is a component of coolant and is present in all water-cooled engines. In the lab we are able to detect glycol at very low levels. Combined with wear metal data it is possible to detect not only the initiation of a coolant leak in the motor, but also isolate the location between the upper and lower cooling system. This is part of all oil analysis done on automotive and diesel engine oil samples.