Base oils are defined as having a viscosity index ranging from 80 to 120, less than 90 percent saturates, and more than 0.03 percent sulphur. These oils can be used in environments ranging from 32 to 150 degrees Fahrenheit. Base oils from Group I are refined using a solvent, which is a less complex refining method. They are the least expensive base oils available because of this.

Base oils are described as having a viscosity index between 80 and 120, more than 90 percent saturates, and less than 0.03 percent sulphur. They are frequently produced by hydrocracking, a trickier method than the one used for Group I base oils. These oils have better antioxidation capabilities than Group I base oils because all of their hydrocarbon molecules are saturated. In compared to Group I base oils, they also have a clearer colour and are more expensive. Group II base oils are nevertheless becoming more and more prevalent on the market and are priced quite similarly to Group I oils.

Base oils have a viscosity index above 120, more than 90% saturates, and less than 0.03 percent sulphur. These oils are typically substantially hydrocracked (greater pressure and heat) and refined even more than Group II base oils. Purer base oil is the goal of this extended process. Group III base oils are sometimes referred to as synthetic hydrocarbons even though they are made from crude oil. These oils are likewise becoming more and more common, just as Group II base oils.

PAOs, or polyalphaolefins, are group IV basic oils. Synthesising is the method used to create these synthetic base oils. They are ideal for usage in extremely cold and hot environments because of their substantially wider temperature range.

All other base oils, such as silicone, phosphate ester, polyalkylene glycol (PAG), polyolester, biolubes, etc., are categorised as Group V base oils. To improve the qualities of the oil, these base oils are occasionally combined with additional base stocks. An illustration would be a polyolester- and PAO-based compressor oil. Esters are typical Group V base oils that are utilised in a variety of lubricant formulations to enhance the base oil’s existing qualities. When compared to a PAO synthetic base oil, ester oils offer superior detergency and can withstand more usage at higher temperatures, extending their useful life.