Since manufacturers and users are always looking for superior products that extend equipment life, the practice of analyzing used oil has been around since engine lubricants were first introduced. Laboratories that perform oil analysis on the many lubricant brands and formulations have been vital to the development of new products.

Prior to the 1970s, conventional motor oils contained low grades of base oils and low levels of additives and lacked in performance and long drain intervals.

But a lot was happening in the automotive, fuel and lubricant industry in the 70s. Higher fuel prices were common, unleaded gasoline was mandated and engines with emission systems were introduced. The EPA started to demand automobiles with cleaner running engines and longer oil drain intervals, and soon after that, the American Petroleum Institute (API) began working with automakers to develop higher standards for engine lubricants. About the same time, Mobil introduced Mobil 1, a fully synthetic engine oil that offered benefits over conventional oils of the time.

More than 30 years later, conventional oils are not the same. Using high-quality base oils and the latest additive technology, today's conventional engine oils offer:

-Low temperature start-up and performance

-Resistance to high temperature

-Better wear protection

-Deposit protection

-Extended drain intervals

-Energy conservation

The most current API service classification for gasoline engines is SM, GF-4. The service classification for diesel engines is CI-4 plus. Products with these classifications meet just about all engine manufacturer performance levels.

Oil analysis technicians frequently are asked whether synthetic lubricants outperform conventional or mineral base oils. There is no definitive answer to that question.

By definition, a synthetic lubricant is "a lubricating fluid made by chemically reacting materials of a specific chemical composition to produce a compound with planned and predictable properties." Its key benefit is the ability to resist changes in viscosity in low temperature performance and high temperature oxidation stability. This means synthetic oil stays in viscosity grade for a longer drain interval than conventional oil.

Oil analysis considers three main components: machine wear, contaminants and lubricant condition. There are several factors examined in each category. Even so, it is difficult to identify a significant benefit of synthetic over conventional oil when performing an analysis.

Current conventional oils perform very well. The oil drain of synthetic and conventional oil is based more on contaminant level in used oil than time or mileage. An important function of oil is to hold contaminants in suspension, as many contaminant particles are too small for oil filters to remove.

There is a clear advantage to synthetic lubricants in many industrial lubricant applications. Gear boxes and drive trains that are not exposed to contaminant-like combustion gases may see extended drain capability with a synthetic lubricant.

Servicing engines within the manufacturer's oil drain recommendations is important, and extended drain intervals should be accompanied with close monitoring from an oil analysis program. Working closely with a good lubricants company that knows the original equipment manufacturer recommendations—and has an oil analysis program—can help you determine any advantages of synthetic oil over conventional oil.

Don North directs product development and lubricant sales at MFA Oil.