There are five specific categories of base oils. These categories define the type of base stock the oil is formulated from. The categories are as follows. Note that the base oil group category is followed by the manufacturing method (in bold print) and then a description of the oil ch category.

Group I - Solvent Freezing :
Group I base oils are the least refined of all the groups. They are usually a mix of different hydrocarbon chains with little or no uniformity. While some automotive oils on the market use Group I stocks, they are generally used in less demanding applications.

Group II - Hydro processing and Refining:
Group II base oils are common in mineral based motor oils currently available on the market. They have fair to good performance in lubricating properties such as volatility, oxidative stability and flash/fire points. They have only fair performance in areas such as pour point, cold crank viscosity and extreme pressure wear.

Group III - Gydro processing and Refining:
Group III base oils are subjected to the highest level of mineral oil refining of the base oil groups. Although they are not chemically engineered, they offer good performance in a wide range of attributes as well as good molecular uniformity and stability. They are commonly mixed with additives and marketed as synthetic or semi-synthetic products. Group III base oils have become more common in America in the last decade.

Group IV - Chemical Reactions:
Group IV base oils are chemically engineered synthetic base stocks. Polyalphaolefins (PAO's) are a common example of a synthetic base stock. Synthetics, when combined with additives, offer excellent performance over a wide range of lubricating properties. They have very stable chemical compositins and highly uniform molecular chains. Group IV base oils are becoming more common in synthetic and synthetic-blend products forautomotive and industrial application.

Gropu V - As Indicated:
Group V base oils are used promarily in the creation of oil additives. Esters and polyolesters are both common Group V base oils used in the formulation of oil additives. Group V oils are generally not used as base oils themselves, but add benefical properties to other base oils.


24 May 2016