Do today’s new cars still have to be broken in? If so, what does this entail?

The answer is yes, brand-new vehicles still need a break-in period. Breaking in refers to the period during which you operate a new car, or a car with newly replaced parts, with a certain amount of care so that its components eventually adjust to each other and work together properly.

The break-in period for a new automobile is generally considered to be somewhere in the range of the first 5,000 to 6,000 kilometres, but most experts agree that the first 3,000 kilometres are particularly crucial. For the first 800 kilometres, one should (ideally) not be too hard on the engine, by taking care not to exceed 3,000 rpm on the tachometer (or, at the very least, not going higher than half the manufacturer’s maximum recommended “revs”). Your owner’s manual lists the various recommended rpm ranges for each gear, so for the first 800 kilometres, you want to try not to exceed half the maximum of each range. If your car is equipped with a manual transmission, you decide when to shift gears, so it’s that much more important to respect the rule. This doesn’t mean you have to “baby” your vehicle during the break-in period: it means respecting these guidelines at first, all the while remaining relatively “firm” in your driving style.

Obviously, you don’t want to exceed the posted speed limits. You should also avoid excessive loads on the vehicle (e.g., pulling a trailer) and excessively long idling. You can also try the following strategies:

  • Avoid heavily travelled roads so you can “put your car through its paces”: acceleration, deceleration, braking, shifting up and down;
  • When climbing hills, downshift so that you don’t put too much strain on the engine, and respect the recommended rpm range (if your car is equipped with a manual transmission);
  • After a cold-weather start, let the engine idle for a while (adjust the time according to the temperature) so the motor oil has enough time to circulate properly.

Starting at around 800 to 1,000 kilometres, once the engine has reached its running temperature you can begin to accelerate a bit more aggressively and rev the engine more. As the kilometres accumulate on the odometer, you can rev the engine higher before shifting and start to use the full range of the engine’s power.

Ah, 3,000 kilometres at last! You can start to use your vehicle normally. If you want to hitch a trailer to it, you can. Keep in mind that the break-in period isn’t quite over yet, though: it will continue for another 2,000 to 3,000 kilometres, but you don’t have to be as strict.

To summarize these “best practices” for breaking in a new vehicle: don’t rev too high, and avoid sustained periods at high speed; i.e., occasionally vary the pace insofar as the situation allows you to do so safely. Your engine isn’t the only thing that will be “thankful” for respecting the break-in period: the drive shaft, shocks, brakes and even your tires will benefit from this extra care taken early in the game. You also want to avoid excessively brisk starts, sudden stops, taking turns too tightly and shifting gears too quickly (with a manual transmission) when possible.

Experts say a breaking-in period is also a good idea if you’ve replaced any major component of your vehicle (even new tires need to be broken in!). With new brake pads or brake shoes, for instance, gradually increasing the intensity of braking will give the parts time to wear equally and ensure maximum effectiveness and lifespan.

Before you shut off the engine

Let the engine run at normal idle speed for a few seconds before shutting off the ignition. You should not rev the motor at this point, as some people suggest. Doing so does nothing to improve re-start capability, and will only increase the risk of pre-ignition (i.e., the engine keeps running even after the key is turned to OFF).