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What Is Synthetic Oil?

Posted by Auto.com Staff | Jan 3, 2019

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jbfatass/Twenty20

When it comes to motor oil, it can seem like there are as many options as there are opinions. And with car engines that are more technologically advanced than ever before, it may seem a little intimidating when trying to figure out what kind of motor oil is right for your engine. Heat and extreme temperatures can test the limits of any motor oil. The best advice is to use whatever engine oil your owner’s manual recommends – and these days, it seems like that is always some kind of full synthetic motor oil. But what is synthetic motor oil, and why is it recommended for your engine?

Conventional and synthetic motor oils may start with the same base crude oil, but how they’re processed from that point on is what sets them apart. Conventional oils would typically be refined and combined with additives to create the oil blends that they require. Synthetics on the other hand, are broken down to their base molecules and then recombined from the bottom up, often with improved additives. This not only allows for improved purity, but also for more control over what goes into the oil and in what proportions. With tighter tolerances in some of today's high-performance engines, that can be extremely important.

You may remember the days when oil changes for your engine were recommended every 3,000 miles You may have also seen some oils which claim protection for 10 or 15,000 miles. This is because synthetic oil takes much longer to break down and degrade than conventional oil would in the same high temperature environment. Even with conventional oils, the 3,000-mile rule has always been a topic for debate. What isn’t so debatable, though, is that synthetic oil technology has improved drastically in recent times. Many experts agree that 3,000 miles is often too short of an oil change interval with most any modern oil, synthetic or not.

Motor oils have specifications far beyond their viscosity (10w30 or 20w50 for example) and there can be a dizzying array of numbers and specifications that a single oil blend might meet. Sometimes these designations can be more generic SAE (Society of Automotive Engineers) specifications. Other times this can be a brand or manufacturer specific designation. This is why it is important to consult your owner’s manual when selecting the right oil for your car. Don’t be afraid to spend a little extra money for the right oil. It might seem expensive now, but with the longer synthetic oil change intervals and the added peace of mind it can be money well spent.