Modern Engines Prefer Synthetic Motor Oils
Synthetic motor oils are premium products that offer many benefits over mineral motor oils. Although more expensive, they last longer and give better engine protection. Their low pour point makes them ideal for starting engines in cold weather, and high temperature stability gives increased engine protection to hardworking cars and trucks. Auto manufacturers have taken advantage of the properties of synthetic motor oils and specify them for new engines. These engines, manufactured to tighter tolerances with direct fuel injection, variable valve timing, and turbo charging, produce more horse power yet use less fuel and produce fewer emissions
What Is Synthetic Motor Oil?
Synthetic oil has uniform properties when compared to conventional mineral lubricating oils. Conventional motor oil is made from Group I and II base oil stocks blended with additives. The oil contains hydrocarbon molecules that vary in length, so some are light liquids and others are heavy. This contributes towards the tendency of conventional mineral oils to solidify in cold weather and evaporate when hot. The oil contains residual molecular compounds that detract from the lubricating properties and contribute towards sludge in engines. Additive packs improve oil properties but deteriorate over time. This is why conventional mineral oil change requirements are so frequent. Synthetic motor oil is made from Group III and IV base oil stocks that have uniformly sized hydrocarbon molecules and virtually none of the contaminants found in Group I and II base oils. The uniformity of the oil contributes towards its excellent performance, especially the low and high temperature performance.
Types of Synthetic Oil
Synthetic oils are made from Group III and IV base oil stock. Group III base oil is high-quality mineral oil that has gone through a process called severe hydrocracking. This process takes place at 650 °F and 1,000 psi where the different hydrocarbon molecules are broken into shorter uniform sized molecules. Impurities such as sulphur and nitrogen are removed. Waxy compounds are subsequently removed by catalytic dewaxing and wax hydroisomerization. The resulting oil is chemically modified Group III mineral base oil. Group IV oil is a group of chemically synthesized products called polyalphaolefins (PAO) that are manufactured from ethylene. Lubrication oils made from Group III and Group IV base oil stock have similar properties and outperform conventional mineral oils. There is another base oil group, Group V, which includes specialty synthetic oils that are used as oil additivesand for other specialized applications. In Europe, oil manufactured from chemically modified Group III base oil is called HC synthesis or synthetic technology oil and that from Group IV base oil is known as fully synthetic oil. In North America, all oil manufactured from Group III and Group IV base oil is called fully synthetic oil. In practical terms, there is little difference in the technical characteristics of synthetic oil manufactured from Group III and Group IV base oil stocks.
Difference between Synthetic Oil and Conventional Oil
Conventional lubrication oil is simply refined crude oil of a certain viscosity range that has been blended with an additive pack to meet the U.S. API specifications or, alternatively, the European ACEA specifications. Conventional oil contains a mixture of hydrocarbon compounds that all have different properties. These include paraffin chains and cycloparaffins that form the basis of the lubricating oil as well as volatile aromatics that are chemically reactive and form black sludge. Other impurities include waxes and a number of compounds containing nitrogen and sulfur. It is the presence of the aromatics, waxes, and other impurities that limit the service life of mineral oil and contribute toward engine wear. Synthetic oils, whether manufactured synthetically or derived from highly refined API Group III base oils, contain a smaller variety of compounds with little variation in their properties. The level of impurities present in these oils is lower than that found in mineral oils. Due to the negligible quantities of impurities, synthetic oils exhibit far more stable properties than mineral oils, and to a large extent, their service life is only limited by the life of the additive packs. Synthetic oil offers better engine protection than mineral oils in terms of heat, cold, wear, and sludge buildup.