Pouring synthetic oil into an engine

If you’re debating on whether to try synthetic oil for your vehicle, you’re probably wondering, “Are synthetic oils worth it?” Oil is the lifeblood of your powertrain, and it’s widely understood that purchasing the correct viscosity is critical to ensuring your engine never skips a beat. But start talking about synthetic and organic oils and the conversation quickly will descend into debate. Despite their prevalence in new cars, the merits of synthetic oils remain a hot-button topic.

The facts, however, don’t lie: synthetic oil can indeed make a difference in the health of your engine. A study by AAA found that synthetic oil reduces engine wear by as much as 47% compared to conventional and semi-synthetic oil – all while allowing longer intervals between oil changes.1

The secret behind synthetic oil’s superior protection is due to a number of factors. To fully understand why synthetic is well worth the money, it’s important to consider the different types of oil, their formulation, and their characteristics.

Synthetic Oils vs. Conventional and Blended Oils

Pouring synthetic oil into engine during oil change

Popular oil viscosities such as 5W-30 come as either conventional oil, a blended synthetic oil, or a full synthetic oil. Let’s consider all three in detail:

Conventional Oil

The cheapest of these is conventional oil. These oils are light on additives and chemical altering and are distilled from a lower grade of crude oil than their synthetic counterparts.2

As the conventional oil breaks down over time, it loses its ability to regulate engine temperature and sufficiently lubricate parts. Go long enough without an oil change and conventional oil with thicken to the point where it becomes sludge. That’s when the oil, completely depleted of its lubricating properties, clumps together into a mucky consistency that can destroy the engine.

Synthetic Oil

Synthetic oils aren’t immune from breaking down – all oils eventually lose their lubricating property over time, hence the need for regular oil changes in all combustion-powered vehicles – but they’ve been chemically altered with artificial compounds that mitigate deterioration.3

When synthetic oils wear out, they don’t lose their ability to lubricate as dramatically as conventional oil. Used synthetic oil might be slightly thicker than a new oil, and look a few shades darker in color, but overall it doesn’t suffer from the same rate of physical and chemical degradation as conventional oil. That’s why you can go so long between oil changes with synthetic oils – sometimes as far as 10,000 or 15,000 miles.

Another notable characteristic of synthetic oil is its viscosity, or flow rate.4 Many modern engines are turbocharged, and the inner workings of the turbocharger require proper lubrication – and fast, for those times you overslept and need to hot-foot it to work. Due to its lower viscosity, synthetic oil can quickly travel from the sump where it collects to the uppermost portions of the engine, including the turbocharger.

Semi-Synthetic Oil

There’s a third type of oil as well, known as a synthetic blend or semi-synthetic oil. As the name suggests, this type of oil splits the difference between conventional and synthetic blends by only mildly altering the base crude oil with synthetic compounds. These oils don’t offer as good protection as fully synthetic blends but do provide better lubrication and temperature protection than conventional oil.

How Long Does Oil Last?

Oil change with synthetic oil

Traditionally, the rule of thumb for changing your oil was 3 months or 3,000 miles, whichever came first. This remains the case for anyone running conventional oil, but the advent of synthetics has enabled less frequent oil changes. Semi-synthetic oil, for instance, can commonly go for 5,000-7,500 miles before needing to be replaced.

As we mentioned, synthetic oil lasts the longest. Some manufacturers don’t require oil changes for 10,000 miles or more, which for most drivers translates to a single annual oil change.

Even if you don’t drive 10,000 miles a year, you should change your oil at least on a yearly basis. This is true even if you own a garage queen that’s only driven a few hundred miles during the summer season. If you don’t change your oil at least yearly, age alone can contribute to the degradation process, resulting in less effective cooling and lubricating.

Is Synthetic Oil Expensive?

Yes – and no. Compared to conventional oil, you can expect to pay more – maybe as much as $30 or $40 more per oil change if you’re having a repair shop do the work. If you prefer to do your own work, five quarts of synthetic is usually $10-$15 dollars more expensive than conventional, perhaps more if you purchase one of the premium brands such as Royal Purple.

However, though the cost per oil change is higher with synthetic oil, the yearly costs of going with synthetic versus conventional oil tell a different story. Assuming you drive the traditional 15,000 miles a year, you’ll need five conventional oil changes if you follow the recommended 3,000-mile intervals. At $30 an oil change, the total annual cost would be $150.

On the other hand, if you run synthetic oil, you can get away with just one or two oil changes. At a cost of $60 an oil change, you would pay $120 for the year for two oil changes. That’s $30 less per year than the ostensibly cheaper conventional oil.

Are All Synthetic Oils The Same?

No. Every manufacturer enhances their synthetic oils with their own secret sauce in the form of additives and enhancers. These unique chemical formulations give each oil a point of differentiation from its competitors, whether that be superior protection for high-mileage engines or better cold-weather viscosity or maximum engine cooling for high-performance powertrains. Some oils may also be better suited to certain engines than other oils, depending on their composition.

For more on the different synthetic oils, see our article on the Best Synthetic Oils.

Parting Thoughts

Fresh oil of the correct grade and viscosity is key to a smooth-running engine. After all, it’s the oil that courses through the veins of your engine, cooling the hot components and lubricating the meshing gears, the cylinder walls, the valvetrain, and all the other parts and pieces that rub up against each other during normal engine operation. And if you want the best type of oil for the job, go for the full synthetic stuff.

If you neglect your oil changes, you’re condemning your engine to an early death. Be vigilant and give your engine the care it deserves with a quality synthetic oil. Your car, your wallet, and your future self will thank you.

Article Sources

Ride Digest uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Edmonds E. AAA Spills the Truth on Oil Changes. Aaa.com. Published June 6, 2017. Accessed April 20, 2021.
  2. Keegan MC. Car Engine Oil and How It’s Made. Napaonline.com. Published December 2, 2016. Accessed April 20, 2021.
  3. Car and Driver. Synthetic Oil: Everything You Need To Know. Caranddriver.com. Accessed April 20, 2021.
  4. Total. Oil Viscosity and Oil Grades. Total.com. Accessed April 20, 2021.