Maintaining engine lubricating oil is a very important element in stretching the productive life of vehicle engines. Often referred to as the life blood of the engine, the oil circulates through the engine, performing critical functions necessary to maintain engine performance and maximize useful service life.

Engine oil needs to be changed on a regular basis because oils can lose their performance properties over time as a result of heat, contamination and chemical deterioration. Engine oils oxidize and become loaded with soot, wear debris and contaminants that can only be removed by draining the oil. Oxidative matter and acids formed as a byproduct of combustion also degrade the oil.

All of this has a negative effect on the performance of the engine oil, contributing to acid formation and increased wear, which can lead to corrosion, among other things.

Looking inside

Oil analysis can be a benefit to any fleet maintenance program by helping maximize oil change-out intervals and improving vehicle reliability. It is a quick, non-destructive way to gauge the health of an engine by looking at what is in the oil.

Regular assessment of the oil condition is one of the most effective ways to monitor engine wear. Serving as an early warning system, oil analysis can alert maintenance personnel to emerging trends, potential problems or failures so they can perform preventive maintenance repairs while they’re small, rather than wait for costly failures. Plus, oil analysis builds a historic database.

Oil analysis involves sampling and analyzing oil for various properties and materials to monitor wear and contamination in an engine. Sampling and analyzing on a regular basis establishes a baseline of normal wear and can help indicate when abnormal wear or contamination is occurring.

Oil that has been inside an engine for a period of time reflects the possible condition of that engine. Oil is in contact with the mechanical components as wear metallic trace particles enter the oil. These particles are so small they remain in suspension.

Products of the combustion process of an engine also will become trapped in the circulating oil. Any externally caused contamination also enters the oil. Thus, the oil becomes a working history of the engine. By identifying and measuring these impurities, indication of the rate of wear and of any excessive contamination can be assessed.

Oil analysis programs differ in many aspects, including available tests, interpretations and reports, turnaround time, price and more. A variety of instant analysis kits also are available.

Consequently, adequate time and effort needs to be invested in order to choose the program that best serves an individual fleet’s requirements and needs.

Because choosing an oil analysis service is a strategic decision, many aspects need to be considered. Among the key factors to consider are the company’s familiarity with your industry, the company’s reputation, the array of services offered, partnerships in training and whether the company has knowledgeable technical support. In addition, it is important to consider whether the programs are user-friendly.

Employing the data

Although a good oil analysis program can be a major tool in the maintenance toolbox, it will only be as effective as the maintenance personnel that operate the program. If they don’t sample at the recommended intervals, or dismiss warning signs from the oil analysis, the program will be of little benefit.

Present day oil analysis programs are electronic and data can be managed very easily. These programs can generate reports to assist with targeting areas of maintenance that need improvement. 

The knowledge gained from an effective, consistent oil analysis program can assist a fleet with the following:


• Optimizing oil drain intervals

• Increasing equipment reliability and minimizing unscheduled downtime through the prevention of premature engine failures

• Extending component life by knowing how the component is wearing in respect to operating conditions

• Debates regarding the cause of warranty claims

• More precisely tracking operating efficiency and maintenance practices

• Improving vehicle resale value by having a complete engine health history combined with maintenance service records

All of this contributes to helping lower total operating costs. BI

The impact of engine maintenance

Engine maintenance has an effect on oil life and performance as well. Among other things, a poorly tuned engine will have higher fuel consumption, greater thermal loading and create more soot.

This leads to increased oxidation, nitration and soot loading of the oil. This, in turn, brings about more deposits, corrosion, wear, potentially stuck rings, diesel particulate filter plugging, etc.

Such maintenance issues also can lead to premature contamination and deterioration of engine oil and ultimately compromise the protection of an engine’s critical parts.

Additionally, restrictions to radiator air flow and not maintaining the coolant system can result in higher engine temperatures and reduced oil life. Air induction maintenance and maintaining proper air filter integrity is another critical factor to controlling dirt contamination in engine oil.

Poor fuel system maintenance can cause excessive fuel dilution or improper fueling injection into the combustion process. This can cause engine oil dilution, excessive soot loading and increased fuel consumption, all of which can be costly. BI