Maintaining your car: How often should you change the oil?

If there’s one thing to remember about changing the oil in your car, it’s this: This is not your father’s Oldsmobile.

We’ve all had the 3,000-mile oil change drilled into our heads by dads and mechanics. But cars – and oil – have changed. According to the car site Edmunds.com, oil chemistry and engine technology have improved to the point that most cars can go several thousand more miles than that before changing the oil.

In fact, says Edmunds, a better average would be 7,500 miles between changes, and sometimes up to 10,000 miles or more!

And the California Integrated Waste Management Board, concerned for not only the cost to drivers but also the environmental impact of throwing away good oil, ran public service announcements for several years about the “3,000-mile myth,” encouraging drivers to wait longer between changes.  The board carries a list of cars on its website, suggesting how often they need oil changes.

Most dealers and service outlets recommend following what your owner’s manual advises. Many manuals describe several different types of driving to help you decide: severe or mild (“severe” is sometimes called normal). Short distance, stop-and-go driving, extended idling, muddy or dusty roads all have an impact, too.

Short trips don’t allow the engine and oil to warm up, so the oil can’t warm completely up and thus cannot efficiently absorb the contaminants that result from internal combustion. Longer-distance highway driving extends the oil life much farther.

So what happens if you don’t change the oil often enough?  Well, it won’t run out, it’ll just get dirtier and dirtier – like mopping the floor with a bucket of water and detergent, and not changing the water.

There are scientific ways to know if you need to change your oil more or less often, too. For $25 and a sample of your oil, Blackstone Laboratories in Fort Wayne, Indiana, will compare your sample to what an average car of your make, year, and model looks like.  And some cars have “maintenance minders” that alert the driver when oil life expectancy is low.

For those that don’t, here are some tried-and-true guidelines:

Every 3,000  miles

  • If you own an older car model.
  • When you drive most of the time in rush-hour traffic in the city, you need to change your oil every 1,000 to 3,000 miles.

Every 5,000 miles

  • Newer car models can run longer miles using the same oil, and engine oil has become more efficient. Change your oil based on your car’s optimum operating conditions.

Trust the owner’s manual

  • Newer car models have pre-installed oil-life monitoring systems that help drivers determine when the engine oil needs changing. Older car models base the changing of oil on the mileage and the time.