Buying a New Car? Here's How to Break In Your Engine

Stephen Fogel
March 5, 2019

engine break-in

In the early days of cars, methods of forging, casting and machining were imprecise — that could be bad for engines. Moving parts that came into contact with each other needed an extended period of carefully supervised running time to wear down their imperfections and develop smooth surfaces wherever they touched.

When done correctly, this engine break-in process resulted in less friction, better oil sealing, improved reliability and longer engine life.

These days, manufacturing techniques have produced extremely precise engine parts that mate perfectly with one another when assembled. But if you buy a brand-new car, there are still some specific areas inside your engine that can benefit from a proper break-in period.

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Seal those piston rings

Your engine’s piston ringsare thin, round bands of spring steel that encircle the diameter of the piston. There are two types of rings — compression rings that create a seal between the sides of the piston and the cylinder wall, and oil control rings that clean oil from the cylinder walls so it’s not burned during the combustion process.

It’s essential that the surfaces of the rings and the cylinder walls are as smooth and closely matched as possible. The proper engine break-in process allows the piston rings and the cylinder walls to achieve this, without risking any engine damage in the process.

What’s the best process for engine break-in?

The first step is to check the owner’s manual in your new car. This is where you will get the best guidance breaking in the engine of your specific vehicle. Follow the instructions and you should be fine.

What does the owner’s manual usually recommend? There may be some variation between brands, but most will suggest some combination of these strategies, to be used during the first 500 to 1,500 miles:

  • Drive gently, with no full-throttle operation
  • Don't drive long distances at a steady speed — vary your speeds, and don’t use the cruise control
  • Don't drive over the speed limit on the highway
  • Keep the RPMs in the middle of the range — not too low and not too high
  • Avoid short trips that keep the engine from fully warming up
  • Don't let the engine idle for more than a few minutes at a time
  • Don't tow a trailer
  • Don't shift into lower gears to use engine braking

The remaining piece of the puzzle is to carefully follow the service and maintenance recommendations that are also listed in your manual.

The benefits of a proper engine break-in

By following the engine break-in recommendations in your owner’s manual, you’ll be giving yourself and your car the best possible chance of having a long and trouble-free life together. Other benefits are improved fuel economy, reduced oil consumption, optimal engine performance and better overall reliability.

Stephen Fogel

About the Author

Stephen has been an automotive enthusiast since childhood, owning some of his vehicles for as long as 40 years, and has raced open-wheel formula cars. He follows and writes about the global automotive industry, with an eye on the latest vehicle technologies.

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