Should You Switch To Synthetic Oil in Your Car?

Synthetic oil provides better engine protection and it lasts longer than conventional motor oil. So should you switch? Let's find out.

Motor oil is an engine’s lifeblood. It cleans, lubricates, cools, cushions, and protects engine and other mechanical parts. Synthetic oil, a composite blend of base oils and complex artificial additives, was first produced in the late 1880s.

Used extensively during World War II to protect jet aircraft engines, the automotive industry believed expensive synthetic oil was unnecessary for passenger cars. Then in 1974, Mobil Oil brought the first full-synthetic oil, Mobil 1, to the consumer market. However, it took until the early 1990s for the automotive industry to recognize the many benefits of synthetic motor oil.

Today, synthetic oil is used in mainstream vehicles, as well as high-performance and turbo-charged cars and trucks.

Should You Switch to Synthetic Oil in Your Car?

In most cases, yes. Switching from conventional to synthetic oil is perfectly OK and recommended, even in older high-mileage vehicles.

However, there are some caveats. Based on my research and personal experience, I don’t recommend full-synthetic oils for pre-1990 models or any vehicle made to operate on conventional oil.

Full-synthetic in a well-maintained engine rarely causes problems. But in neglected engines, the same exceptional qualities that make full synthetic so beneficial for your engine can worsen already failing oil seals and gaskets. Refiners now remove nitrogen-containing compounds and other additives found to harm older engines.

Pros and Cons of Switching to Synthetic Oil

Compare for yourself.


Synthetic oil starts from a higher quality base than conventional oil, then goes through extensive refining processes.

State-of-the-art compound additives (antioxidants, corrosion and foam inhibitors, friction modifiers, anti-wear agents, detergents and water dispersants) are added to the super purified oil, producing a product far superior at protecting an engine than conventional motor oil.

Synthetic oil protects by:

  • Preventing deposits from forming on internal engine parts.
  • Removing sludge and deposit build-up.
  • Keeping engine parts cooler while protecting them in climates with extreme temperature fluctuations (0 to 100 degrees).
  • Reducing engine wear by holding sludge, harsh chemicals, contaminates and abrasive particles in suspension until the next oil change.
  • Providing exceptional lubrication and viscosity capabilities that improve fuel economy.
  • Demonstrating excellent hydraulic fluid characteristics critical in variable valve timing engines.
  • Reducing tailpipe emissions.
  • Reducing the number of oil changes. That protects the environment because less used oil ends up in waste water.


These may stop you from switching to synthetic oil:

  • Cost. According to Kelley Blue Book, expect to pay $65 to $125 for a full-synthetic oil change. Conventional oil changes run $35 to $75.
  • It may harm older, neglected engines by washing away deposits.

The pros clearly outweigh the cons. The extra cost of synthetic oil is a worthwhile investment to extend the life of your engine and reduce repair costs.

Can I switch back to conventional oil?

Yes, but why would you want to?

The old myth that you can’t switch back to conventional oil after using synthetic is just that — a myth. Both oils start out as base crude pumped from the ground. The refining process and additives give synthetic oil its exceptional lubricating and wear protection features.

Although you can mix conventional and synthetic oil, don’t. Once mixed, the oil takes on the properties of conventional motor oil, without the advantages of full synthetic.

What About Synthetic Blended Motor Oil?

If the high cost of synthetic oil is holding you back from switching, consider a synthetic blended motor oil. A mixture of synthetic and conventional base oils, synthetic blended comes with comparable additives found in full synthetic oils.

It’s more durable with excellent low-temperature properties. It can go longer than conventional oil between changes, at a lower cost. Although more expensive than conventional motor oil, synthetic blended is worth the price if you plan to keep your vehicle for many years to come.

Bob Lacivita
Bob Lacivita is an award-winning ASE and General Motors auto technician, educator and freelance writer who has written about DIY car repairs and vehicle maintenance topics. His work has been featured in The Family Handyman, a Reader's Digest book and Classic Bike Rider magazine. He has been a career and technical educator for 25 years teaching automotive technology, as well as writing state, federal and organizational foundation grants. He also helped design a unique curriculum delivery model that integrates rigorous, relevant academic standards seamlessly into career and technical education.