Whether you’re a DIY mechanic, take your car to a quick oil-change place, or use a trusted local mechanic or dealer for service, you’ve probably heard about synthetic oil. So, what is synthetic oil, and does it make a difference for your vehicle?

How synthetic oil differs from conventional oil

Synthetic oil is exactly what it sounds like: an engine lubricant created artificially from chemical compounds. Some classes of synthetic oil start with conventional oil as a base that's then chemically altered to produce synthetic oil, while others may be artificially created from other raw materials. In contrast, conventional motor oil (also referred to as standard oil or mineral-based oil), is refined from naturally occurring crude oil.

Highly rated mechanics say synthetic oil does offer specific advantages over conventional motor oil. “With synthetic, the oil’s ability to do its job within the car engine is superior to mineral-based oil,” says Greg Hochhalter, owner of highly rated Auburn Foreign & Domestic Car in Auburn, Wash.

“The primary purposes of synthetic oils are to reduce engine wear during cold start-up and drive-away, and to avoid or reduce oil degradation,” says Sam Bell, owner of highly rated The Lusty Wrench in Cleveland.

In a nutshell, synthetic oil is thinner, resists temperature extremes better and generally lasts longer. You likely won’t notice any difference in how your car performs, but the durability characteristic is the most important from a car owner’s perspective, as it translates to less frequent oil changes compared to conventional motor oil. “The fundamental difference is that synthetic oil can go longer before it starts to break down when compared to conventional oil,” Hochhalter says.

Although recommended oil change intervals vary by vehicle manufacturer, in general, a good rule of thumb to follow is to change conventional motor oil every 3,000 to 5,000 miles. “If you’re using full synthetic oil, we recommend going about 7,500 between changes,” says Leo Jay of highly rated Dere Auto in Seattle. Bell says that with synthetic oil and some manufacturers, intervals between oil changes can be much, much longer: "In some cases as much as 15,000 miles or one year."

Achieving a prolonged oil-change interval will cost you more money with each oil change. Synthetic oil is more expensive, generally costing about twice as much as conventional oil. However, Dere says the longer interval should also factor into your cost consideration, “It can actually be cheaper overall because you’re not paying for the labor on the oil change or the oil filter as often - [with the longer intervalit’s like getting two oil changes for one.”

How to decide if you need synthetic oil

So, how do you know if synthetic oil is right for you? Mike Aronow, owner of highly rated Sunset Auto Imports Services in Hendersonville, Nev., says it all depends on how frequently you prefer to change your oil. “The first question you should ask is, ‘How often do you change your oil?’” he says. “The biggest factor of using synthetic oil versus conventional oil is the longevity of it.”

If you are punctual about getting oil changes, and your vehicle doesn’t already require synthetic oil (more on this later), you may want to stick with conventional. “If you are good about changing your oil when you are supposed to, there is no reason to use synthetic oil,” says David Bulko of AutoAid & Rescue in Van Nuys, Calif. “If getting your vehicle in for service doesn’t always happen on time and you find yourself always going over on recommended change interval, maybe synthetic oil is for you.”

“What I’ve discovered is that people get busy and tend to put oil changes off,” says Carl Roberson of highly rated Carl’s Cool Cars in Las Vegas. “With synthetic, you can put it off a lot longer and be OK.”

But be careful when going extended periods without changing your oil, Bell says: “One of the biggest drawbacks to using synthetic oils is also one of the biggest advantages. Longer service intervals are obviously less hassle for the consumer, but, if you're like most consumers, you'll never even open the hood between oil changes. So, if, for example, you develop an oil consumption problem, you may drive for several months and many thousands of miles with your oil level too low.”

Some vehicles require synthetic oil

Whether or not synthetic oil is right - or required - for your vehicle first depends on what type of vehicle you drive, highly rated mechanics say. New and late-model vehicles from European makes such as BMW, Volkswagen, Mercedes-Benz and Audi typically require the use of full synthetic oil. Bell adds that certain new vehicles from Subaru, some Hondas and Toyotas (typically hybrids), and some high performance cars also require synthetic oil.

“Always check your owner's manual,” Bell says. “If synthetic oil is required, you risk losing any warranty coverage for an engine problem if you fail to comply, even if there is no direct connection between the problem and the oil you chose.”

Why oil changes are important

Considering that an oil change can cost about as much or less than a full tank of gasoline for many drivers, they're a relatively cheap investment to prolong the life of your vehicle. “Oil service is the most important thing you can do for your car,” Aronow says. "Preventive maintenance doesn’t cost money, it saves you money

And whether you use conventional motor oil or synthetic, regular oil changes by a qualified mechanic can help ensure longer life for all your car’s mechanicals. “The most important part of an oil change is not necessarily the actual changing of the oil, nor the new oil itself, but the inspection that well-qualified automotive professionals always include as part of their under-the-hood routine,” Bell says. “Whatever oil you use, someone has to check under the hood from time to time to avoid serious surprises.”