Synthetic oil is a lubricant composed of artificially made chemical compounds; these compounds are made by breaking down and then reconstituting petroleum molecules. Under a microscope, a drop of synthetic oil shows millions of molecules of almost identical size and structure. Similarly, mineral and conventional oil is made using refined crude oil. Fully synthetic oils use a synthetic base stock, are uniquely designed molecule by molecule without the use of petroleum, and contain additives to help the oil break down. A synthetic blend is a mixture of conventional motor oil and synthetic base oils. Adding synthetic base oil to conventional mineral oil provides slightly more protection than using conventional oil alone. There are many types of synthetics with markedly different properties and applications. However, most synthetics used in automotive service are polyalphaolefins (PAO).

Numerous studies have been conducted over the years comparing synthetic oil to conventional mineral oil. Most notably, the American Automobile Association (AAA) has used certified laboratories using American Society for Testing and Materials (ASTM) standardized test methods to study the differences between conventionally marketed motor oils and motor oils marketed as fully synthetic. Even though conventional oil lubricates your car engine adequately in most cases, there are some potential disadvantages to using it. These disadvantages may or may not be noticeable depending on several factors, such as marginal fluidity at extremely low temperatures, thermal and oxidative stability (long-term chemical stability at high temperatures), and viscosity protection (against wear and friction) at high engine loads and temperatures.

When it comes to the price of synthetic or synthetic blends, it is not always black and white. Mineral oil provides adequate lubrication for your vehicle’s equipment, while synthetic oil protects your engine better by using higher quality, more refined base oils. Investing in premium lubrication can slightly extend the life of your compressor. It must be said that there are some exceptions to this concept. One in particular is to expose an equipment to worst-case scenarios long before the end of its normal lifespan. Worst case scenarios include extreme temperatures, forgetting to change oil on time, heavy loads, frequent cold starts, frequent short commutes, poor engine cooling, etc.

In high-performance compressors, there are many high-level lubrication performance expectations, such as the expectation of efficiency and reliability. Synthetics naturally have a higher viscosity index. This means that the viscosity changes less (more stable) as the temperature changes during normal start-up and operating conditions. Viscosity is an important feature of lubricants that forms the film thickness or gap between metal surfaces sliding or rotating against each other. Without this film thickness, excessive friction and wear occur. At extremely low temperatures, it is possible for lubricants (compared to synthetics) to become so thick (high viscosity) that the oil cannot be pumped or circulated effectively within the compressor. Lack of oil circulation can lead to lubricant starvation and equipment failure. Synthetic compressor oils are generally less volatile than mineral oils. This means there is less oil loss into the engine’s exhaust stream, which causes atmospheric pollution. This can also mean less need for makeup oil between oil changes.