The following contains spoilers, so beware! If you were curious as to whether synthetic auto engine oil or conventional motor oil was better for your car, here you go: Traditional oils are second best to their synthetic counterparts.
This is not to say, however, that conventional motor oils won’t do the trick for keeping your car’s engine healthy. Engine oils that meet the lubrication standards set forth by the American Petroleum Institute (API) oil service categories can be relied upon to perform as expected.
However, not all motor oils are the same; some are far more effective than others.
Some, for example, can go longer between oil changes because they continue to perform reliably. For example, the shelf life of synthetic oils is far longer than that of their natural counterparts. If you’d want to know more about the rationale behind that statement, feel free to keep on reading.
What Are Conventional Oils?
A variety of additives are added to a base oil to improve the performance of an automobile’s engine. Base oils are the fundamental component of any lubricating oil, and in most engine oil formulae, they make up anywhere from 80% to 99% of the total.
The American Petroleum Institute classifies all base oils into one of five groups. Base oils, which are produced by refining petroleum crude oil, are the precursors to conventional lubricants, such as those used in automotive engines. Group I, Group II, and Group III are the three primary types of basic oils.
Conventional oils are also known as mineral oils since they are derived from refined crude oil.
Motor oils sold as synthetic oils in some countries may really contain Group III base oils.
What Are Synthetic Oils?
Groups IV and V are where you’ll find most synthetic lubricants, while Groups I, II, and III are where you’ll find most mineral engine oils. Despite what may be advertised, Group IV base oils are commonly used in the formulation of fully synthetic motor oils.
Group IV base oils, in contrast to Group I-Group III base oils, are synthesized in laboratories. Some Group V base oils are derived from mineral sources, but synthetics make up the vast majority.
Groups of Base Oils
The API’s grouping of base oils into distinct categories merits discussion at the present time. Characteristics that divide basic oils into the first five categories.
A neutral oil with a saturation level of less than 90%, a sulfur level of more than 0.03%, and a viscosity index of 80 to 120 is considered a Group I base oil. The first stage in making Group I base oils is cleaning the raw materials with solvents.
Liquid extraction includes processes like refining with solvents. Furfural, phenol, and sulfur dioxide are frequently used in liquid extraction.
Group II base oils include hydroprocessed crude oils. They range from 80 to 120 on the viscosity index and contain more than 90% saturate and less than 0.03% sulfur.
Group II base oils are made using a process called hydrocracking.
Hydrocracking is accomplished by injecting hydrogen into the base oil as it passes over a catalyst bed at temperatures above 343 degrees Celsius and pressures above 1,000 psi. As a result of the subsequent chemical reaction, some of the hydrocarbon molecules are deformed and broken up into smaller fragments.
Group III base oils have a saturate content greater than 90%, a viscosity index greater than 120, and a sulfur concentration greater than 120. You might think of them as Group II oils with a higher viscosity index.
Making Group III base oils requires a very high level of hydrocracking. Hydrocarbon molecules are subjected to more extreme bending and cracking during severe hydrocracking as a result of the elevated temperature and pressure employed.
Because of their high viscosity index, Group III oils are the most stable and efficient oils on the market. Motor oils made with Group III base oils are sometimes marketed as synthetic oils even though they are essentially mineral oils because Group III oil is refined petroleum crude oil.
Since Group IV base oils are not processed from petroleum crude oils, they are not mineral oils. They are artificially created in labs.
All of the PAOs in Group IV are synthetic versions of organic alpha-olefins. A high viscosity index and consistent molecular size are hallmarks of synthetics.
Because they don’t belong in any of the previous groups, the remaining basic oils are categorized here in Group V.
Synthetic, but not PAO, esters, polyalkylene glycol, and silicone are used in the production of Group V oils. Group V might theoretically include mineral oils like refined white oil used in kitchens and beauty salons.
Group V oils are typically found in motor oils as additives to base oils rather than as the major component.
Why Are Synthetic Base Oils Better Than Mineral Base Oils?
As one moves up the API scale, the refinement level of the oil increases.
The stricter refinement methods applied to the feedstock at higher classification levels guarantee a higher concentration of saturates, lower levels of sulfur content, and a higher viscosity index.
The fraction of saturated hydrocarbon molecules in base oil is an indicator of its molecular bond. An increase in the number of saturates strengthens the molecular bond. This means it will be more resistant to oxidation and will last longer.
For this reason, a higher-saturation base oil is recommended.
The naturally occurring sulfurs in crude oil come with both advantages and disadvantages. Because of its antioxidant qualities, it can prevent the oxidation-related breakdown of base oils. It is also commonly found in additives that fortify oils against wear and boost their lubricating properties.
Acids generated when sulfur combines with oxygen can corrode non-ferrous metals, despite sulfur’s protective role. As a result, motor vehicles cannot utilize base oils with excessive amounts of sulfur. This is why it’s important to look for a base oil that contains less sulfur.
The viscosity index evaluates the stability of base oils in terms of their viscosity. Base oils are thick and viscous when cooled, yet thin and slippery when heated.
Oils with a high viscosity index see only tiny changes in viscosity as a result of temperature changes. The effect of temperature variations on the viscosity of low-viscosity-index oils is more pronounced.
Consequently, a base oil with a high viscosity index is recommended.
Synthetic Engine Oils Are Better
Synthetic engine oils are made from Group IV base oils, which are far superior to conventional engine oils made from Group I, II, or III base oils.
Group IV oils are very high in saturates and have a very low sulfur content and a very high viscosity index. You should think about it at your next oil change.