Oil Spectrum Analysis

Explanation of Oil Analysis

The theory behind oil analysis is that as an engine is operated, the metal parts of the engine wear and microscopic particles will remain in suspension in the hot oil. This is measured for both quantity and type by the lab, which uses complex testing and analysis.

All the major engine manufacturers, such as Caterpillar, Cummins, Detroit/MTU, and MAN, offer oil analysis programs through their dealerships.

Oil analysis is also useful as part of my marine survey. I recommend that engines, transmissions, and generators be tested as part of the pre-purchase survey. Though oil analysis is intended as part of an ongoing sampling and maintenance program, a single test can still tell a great deal about the health of an engine.

Lubricating oil reduces friction and wear between moving parts, assists in cooling the engine, and removes contaminants. The wear of these parts generate minute

metal shavings, decomposition of gasket material, ingestion of sand and dust with combustion air, accumulation of soot and sulfur from combustion, and acids formed when condensation combines with the sulfur and other chemicals in the oil.

The analysis is based, when known, on the hours of the engine and the hours on the oil. This is a good reference to relate the parts per million to the actual use. The values are also important indicators of existing severe conditions. The annual analysis reporting is intended to predict mechanical wear and failure of the equipment or a component part. The values for wear metals and silicon are reported in parts per million. The results are evaluated in relation to hours and/or miles on the oil and component, operating conditions, and any other variable that could affect wear element concentrations.

A successful oil analysis program involves the necessary coordination between the laboratory and the user to utilize the program to its maximum benefit. The lab keeps a record of each sample and after a few tests can offer an annual analysis that takes the observed trends into account. When picking a lab make sure that they have a good background in your type of equipment. You might want to check with your local engine distributor for his recommendation. Each lab varies in the tests they perform but there are certain basic tests that should be included. The first is physical data: viscosity of the lubricant and the presence of water, fuel, dirt, and other solids in the oil. Lubricant diluted by water or antifreeze solution indicates that coolant is leaking into the oil, usually from a blown head gasket or cracked head.