Consumers can get even more confused by ad slogans like "formulated for stop-and-go driving." One would certainly hope that any motor oil could handle the rudimentary challenge of keeping a car running that had a tendency to stop and go.
There are meaningful differences in motor oils, and choosing the right one can make a major impact on how well your car runs. Selecting the right oil is often the fastest and cheapest way to improve your car's performance and reliability.
Two factors determine how well motor oil will perform in your car: one is the base oil; the other is the combination of chemicals (additives) added to the base oil.
The two primary types of base oils used are mineral and synthetic. Mineral oils are by-products of refined crude oil. Refining helps to reduce the impurities but leaves molecules of all shapes and sizes. Synthetic oils are manmade compounds whose molecules are all the same size and shape; consequently, synthetic oil reduces friction and performs significantly better than mineral oils.
There has been sizable growth in the use of synthetic oils over the years. In fact, synthetic oils are often what the factory uses in many new performance and luxury cars.
Regardless of the base oil used, chemicals must be added to give motor oil the characteristics needed to do its job. Typical additives introduced to base oil include detergents to reduce the formation of residue, defoamants to deter absorption of air, anti-wear agents, antioxidants and others.
Although additives comprise only 15 to 25 percent of motor oil, they can impact a lubricant's performance much more than the base oil. For instance, mineral-based motor oil with a good additive package can outperform synthetic motor oil with a mediocre additive package.
There is no easy way for a consumer to determine the quality of a motor oil's additive package. Price is often an indicator of quality, since the more advanced additives cost more to produce. Performance is the ultimate measure of additive-package quality.
Advances in Lubrication
Some of the greatest technological advances in lubrication are seen in chemical additives. These breakthroughs have been developed by a handful of companies that specialize in high-performance lubricants, as opposed to major oil companies whose primary focus is refining and selling crude oil by-products such as gasoline and other fuels.
The easiest way to select motor oil is to follow the good/better/best model:
-Good - mineral-based (regular) motor oils. These are the cheapest and most widely available oils. They typically use standard additive packages that provide minimum levels of performance and protection.
-Better - synthetic motor oils. These man-made oils are more expensive that mineral-based oils but are still widely available. Their performance advantages come predominantly from the synthetic base oil used. They have a longer service life and offer some improvements in protection. They typically use the same additive packages found in mineral-based oils.
-Best - technologically advanced oils. Although they significantly outperform mineral based or synthetic motor oils, they are about the same price as standard synthetic motor oil. They are typically only available through auto parts stores and select oil change centers. These oils primarily differ in their use of more advanced, proprietary additive technologies.
Still confused? For a used car with little life left in it, stick with the cheap mineral-based motor oil. For a car you plan to keep for a few years and want to get a little better performance from, you should at least upgrade to synthetic motor oil. To get the most performance out of your car, truck or RV, or to protect a vehicle you really care about and want to last, upgrade to high-performance motor oil.