Oil Debris

• As surfaces rub together, friction between those surfaces causes them to wear. Minute particles of the surface materials are removed from the surfaces. Larger particles are trapped by the oil filter, but smaller particles become suspended in the lubricating oil.
  
  Oil debris analysis uses instruments such as the spectrograph to identify the type and concentration of particles in the oil, including copper, iron, chromium, lead, tin, aluminum, molybdenum, silicon and sodium.
  
  By monitoring the results of the analysis over time, it is possible to identify trends such as sudden increases in the concentration of particular elements that may indicate the impending failure of a component.
  
  

Oil Contamination

• Engine combustion creates by-products such as soot and sulfur compounds. Oil analysis can identify other contaminants also.
  
  Glycol (antifreeze), fuel, and water can all leak past seals and contaminate the oil, reacting with the oil's additives to reduce their effectiveness.
  
  Fuel dilutes the oil, lowering its viscosity and accelerating wear.
  
  Water accentuates the actions of acids in the oil, increasing the risk of corrosion. Excessive water contamination can create a buildup of oil sludge that can block oilways, possibly causing sudden failures due to lack of lubrication.
  
  

Oil Additives

• Engine oil contains additives that help the oil to perform well and increase its life. For example, additives help to neutralize acids produced by a cold-running engine, to reduce oxidation in the oil and to maintain the viscosity of the oil in use.
  
  Analysis of the performance of these additives over time can help to indicate where one particular additive may break down while the oil is otherwise still effective. In these cases, it may be possible to add fresh additive to the oil rather than change the oil, a procedure known as "oil sweetening."
  
  

Significance

• It's clear that an effective oil analysis program is important for both safety and economic reasons.
  
  Analysis can indicate accelerated wear and actual component failures such as fuel and water seals. Increased debris levels in the oil may forecast impending component failures.
  
  Oil analysis offers direct evidence of the effective life of oil and of individual oil additives, enabling businesses to set oil change intervals based on data rather than guesswork. If a particular additive is breaking down before the oil otherwise loses its effectiveness, the addition of fresh additive to "sweeten" the oil can be more cost-effective than changing the oil.
  
  

Considerations

• To be most effective, oil analysis depends upon the accurate interpretation of results. It is easy for an analyst to jump to incorrect conclusions if they are not aware of all the variables that can affect the oil sample, such as the type of equipment the oil sample is from, the current life of the equipment, any maintenance or component replacements that have occurred since the last analysis, the work environment, and so on.
  
  The SACODE program is a typical systematic analysis program, where "SA" represents basic oil properties, "CO" represents oil contaminants, and "DE" represents oil debris. The program methodology takes an analyst through a checklist that helps to identify all the conditions that may impact the analysis.