Synthetic oil is a man-made lubricant that consists of artificially made chemical compounds. Synthetic oils are typically created from chemically modified materials such as petroleum components, but the base material is almost always distilled crude oil. Any additional additives and the actual synthesis process for creating synthetic oil varies among producers and is considered a trade secret.
Synthetic Oil: Overview
Artificially created lubricants are often used as a substitute for petroleum-based oils, which are required to operate in extreme temperatures.
Synthetic oil was developed in 1929 and has been used in everything from daily-driver and high-performance vehicles to jets. During World War II, when Allied Forces restricted oil access to Nazi Germany, the latter relied on synthetic oil to fuel the German military. In the 1970s, the American Energy Crisis drove efforts to create better artificial oils as a way of improving fuel economy.
Today, certain engines, such as aircraft jet engines, require synthetic oils. Although synthetic oil was once largely found in high-performance vehicles, it's being used in more mainstream engines so that automotive manufacturers can achieve improved fuel efficiency.
Synthetic Oil vs. Conventional Oil: FAQs
Is synthetic oil better for your car's engine than conventional oil?
Yes. Although conventional oil provides adequate lubrication, it doesn't compete with synthetic oil's overall engine protection and performance.
Synthetic oils are created with base oils which are of a higher quality than conventional, less-refined base oils. These higher quality base oils make synthetics:
- Less likely to acidify and oxidize
- More chemically stable
- Harder to break down and lose desired qualities
Consumer Reports says that fully synthetic oils provide superior engine protection and performance over any synthetic blend or conventional motor oil.
What is the difference between synthetic and conventional oil?
Visually, there is no difference. The two major differences between synthetic and conventional oil are a bit more subtle.
First, the way the oils are made create a clear distinction.
For example, conventional 5W-30 motor oil is a petroleum-based oil that is thick at low temperatures and thin at high temperatures. To change this variance, oil manufacturers use additives to change the oil's properties, reducing its viscosity at lower temperatures and thickening the oil at higher temperatures. When it's freshly made, conventional 5W-30 motor oil acts like its synthetic counterpart, but over time, the chemical additives break down or vaporize, returning the oil to its original consistency.
By contrast, synthetic oils are designed to match a specific type of multi-grade oil from the beginning. Even without additives, a synthetic 5W-30 motor oil will not degrade or change viscosity—it may only become slightly thicker from contaminants.
Does synthetic oil last longer than conventional oil?
In general, yes, synthetic motor oil provides longer intervals between oil changes, but it depends on the brand of oil you use. Certain brands recommend you have your oil changed every 3000 or 5000 miles. Other recommendations range from 7500 to 20,000 miles. Other factors that influence the time between oil changes include driving conditions and your driving style.
Regardless, you should follow the oil change recommendations in your owner's manual while your vehicle is still under warranty. You should also take your vehicle for more frequent oil changes when first switching to synthetic motor oil because the engine probably has a buildup of deposits and sludge.
What are synthetic oils made from?
Full synthetic motor oil uses the highest possible quality base oil as a starting point, but the industry specifics are a bit murky. Aside from the base oil, synthetic motor oil often incorporates additives to create the final product. Even though no two brand's synthetic oils are equal, full synthetics still provide better protection than conventional oils or synthetic blends.
Advantages of Synthetic Oil Over Conventional Oil
Since synthetic oils are created using complex processes, they can achieve the precise molecular qualities required for specific applications.
The processes used to make synthetic oils allows oil companies to remove impurities otherwise found in crude oil. They can then tailor the oil molecules to meet the specific demands of modern engines. Thanks to this level of customization, synthetic oils provide superior levels of protection and engine performance than conventional oils.
Synthetic oils also offer the following advantages:
- Greater engine protection. Consider that a car's engine parts move at high speeds and are always in contact with one another. In extreme environments, those engine components can wear down. Your motor oil is the only thing providing a protective element between those moving parts. Unlike synthetic blends or conventional oils, fully synthetic oils won't break down and will protect your engine for longer—sometimes as much as 250,000 miles.
- Cleaner engine. As motor oil circulates through your vehicle's engine, deposits form. Conventional oils form sludge from these deposits over time, reducing your engine's efficiency and lifespan. Full synthetic oils, by contrast, contain fewer impurities and resist sludge and deposit formation.
- Better viscosity. At both low and high temperatures, synthetic oils enjoy better viscosity and stability than conventional oil or synthetic blends. Full synthetic oils are designed to flow quickly in winter temperatures and resist extreme heat, allowing your engine to run smoothly year-round.
- Turbocharger protection. As more cars are built with smaller engines and turbochargers, synthetic oils flow quicker to critical parts, creating the proper lubrication your engine needs. By contrast, conventional oils break down faster under turbocharged conditions. Using a full synthetic option keeps your turbocharged vehicle operating at peak performance.
While synthetic oils offer superior performance, they are substantially more expensive per volume than conventional motor oils. They also pose potential problems in terms of decomposition in certain industrial environments.
Synthetic Oil Change Interval
Most synthetic oils are rated to last between 10,000 to 15,000 miles, or six months to a year. Manufacturer recommended ratings are typically applied to "normal driving," and don’t reflect severe driving conditions that may require more frequent oil changes.
If you drive less than 10 miles a day and don’t drive on highways, you may need to change your oil more often because your engine likely isn't heating up to a temperature high enough to boil off condensation that accumulates in the system, and therefore your oil can break up more quickly and need replacement often. In such cases, it may be a good idea to change your oil sooner than your rated mileage recommendations.
Information and research in this article verified by ASE-certified Master Technician Duane Sayaloune of YourMechanic.com. For any feedback or correction requests please contact us at research@caranddriver.com.
Sources:
https://www.consumerreports.org/car-maintenance/should-you-use-synthetic-oil-in-your-car/
https://www.idrivesafely.com/defensive-driving/trending/synthetic-oil-vs-conventional-oil
https://www.caranddriver.com/shopping-advice/a27078539/synthetic-oil-change-interval/
https://www.caranddriver.com/shopping-advice/g24400723/best-synthetic-motor-oil/
