Why is quality motor oil important?

Using Quality Motor Oils

Some car engines can benefit from synthetic oil more than others.
Some car engines can benefit from synthetic oil more than others.

Before we discuss the oil you should use, let's look at three different types of oil that you may have heard about:

  • Mineral oil is created from refined crude oil. It's the least expensive option and works just fine in most everyday vehicles.
  • Synthetic blend oils are made in a laboratory and are often designed for older and "high performance" engines. They're more expensive and offer longer life and lubrication. As the name indicates, synthetic oil is mixed with mineral oil to some degree.
  • Fully synthetic oils contain no mineral oils. They're often used in industrial applications, and have incredibly high longevity. They tend to be the most expensive oils available.

Different cars require different types of motor oil. For example, a brand new Toyota Corolla probably doesn't need fully synthetic oil, but an older Chevrolet Corvette might benefit from it. Remember, synthetic oils are more expensive, so you could end up paying for something you really don't need.


Lots of companies that create synthetic blend and fully synthetic oils advertise gains in horsepower or fuel economy. Take these ads with a grain of salt -- while they may improve efficiency somewhat, the difference may not be all that noticeable to you as a driver. However, some new oils are formulated for older, "high-mileage" engines, and these could be beneficial to your car's engine if you have a vehicle with more than 100,000 miles (160,934 kilometers).

At the end of the day, it's best to consult your owner's manual when you're choosing oil for your car's engine. Just remember to check for the API seals so you know you're getting quality oil. And while there's an endless debate over which brand of motor oil is supposedly the best, if you know how to spot a quality motor oil (and you change it at the recommended intervals), your car's engine will likely run for a long, long time.

For more information about motor oil and other related topics, follow the links below.

Related HowStuffWorks Articles

More Great Links

  • All About Oil
  • Used Motor Oil Collection and Recycling - American Petroleum Institute
  • Motor Oil Matters


  • American Petroleum Institute. "API Motor Oil Guide." (May 26, 2010)
  • American Petroleum Institute. "Impact of Low Quality Oils on Engine Wear and Sludge Deposits." (May 26, 2010) vs SL comparison.pdf
  • "The Engine Oil Bible." (May 26, 2010)
  • Weissler, Paul. "How To Pick The Right Motor Oil For Your Car." (May 26, 2010)