Do You Have to ‘Break In’ a New Car?

Subaru recommends owners of its new cars keep it below 4,000 RPM for the first 1,000 miles (1,609 kilometers), regardless of the car model. Subaru of America

“Drive it like you stole it” is a common and arguably overused phrase to describe the way “real” car enthusiasts think everyone should behave behind the wheel: pushing a car to its limit at every opportunity. And it’s tempting, to say the least, to really explore the potential of a brand new car. After all, you’ve probably been waiting a long time for the chance to call it your own. But cars actually need a “break-in” period before you test them to the max. Here’s why.

Breaking in a new vehicle is really about the engine. The break-in — or mechanical run-in — period is designed to begin to wear the engine evenly and smoothly with low, consistent pressure, normal operating temperature and smoothly flowing oil. The goal is to get the engine’s piston rings, which expand, contract and flex, to seat properly on the cylinder walls. If there are imperfections in the pistons or the cylinder walls from the manufacturing process, working the engine too hard and too soon can wear down those imperfections too quickly. That leads to “hot spots” within the engine’s cylinders, which can cause problems in the years to come.

Most drivers have no idea what’s going on inside their car’s engine at any given time or, more to the point, how their behavior behind the wheel affects it. Rest assured that proper, manufacturer-recommended break-in procedure is designed to enable the engine to do what it needs to do. The benefits, according to CNET, are better fuel economy, better performance, less chance of burning or leaking oil and overall longer engine life.

Break-in Times Vary

Examples of break-in periods for specific vehicles vary, depending on the make, model and other variables. For instance, Nissan suggests its GT-R should not be driven at more than 50 percent throttle or over 3,500 RPM (revolutions per minute) for the first 300 miles (482 kilometers). Chevrolet has a two-stage break-in for its famed Corvette: For the first 500 miles (804 kilometers), it suggests drivers stay below 4,000 RPM and avoid driving at full throttle. Subaru recommends owners keep it below 4,000 RPM for the first 1,000 miles (1,609 kilometers), regardless of the car model.

The Acura NSX, on the other hand, has its break-in period completed at the factory before the car is delivered to the customer. The engine is manipulated manually and via computer for the equivalent of 150 miles (241 kilometers), below 4,000 RPM and at varying engine loads (essentially, simulating driving in different types of traffic and at different speeds). This process ensures an even break-in and allows new NSX owners to immediately drive the car at peak performance.

How to Condition Your Car

Better manufacturing practices have shortened the average conditioning period, but can’t yet eliminate it entirely. Engines are stronger, their parts are made with more precision and they’re filled with higher-quality oil. Despite these improvements in engine performance and longevity, there are some recommendations on how you should still drive your new car for the first 500 to 1,000 miles (1,609 kilometers) or the interval recommended in your owner’s manual:

Avoid pushing the engine up to redline.
Be particularly careful if it’s a high-performance car.
Don’t floor the gas pedal.
If it’s a manual transmission, shift gears before it redlines.
Don’t use cruise control. It’s important for the engine to go through different RPMs.
If possible, avoid short trips that don’t allow the car’s engine to warm up to normal operating temperature.
Avoid towing as it can put a heavy load on the engine, and because the car’s brakes and tires require increased stopping distance (see Now That’s Interesting).

Is There a Better Way?

There are some fans of an alternative method, which is to drive the car as hard as possible right off the dealer lot, believing that getting the engine hot and highly pressurized right off the bat is the best way to create that seal. There is some anecdotal evidence to support this method, and it’s certainly more fun than babying the new car you’d really rather show off.

“The break-in period is a ‘general’ recommendation,” Ron Kiino, manager of product communications for Subaru of America, says via email. “Usually for the first 1,000 miles, the break-in period can be different for certain types of cars or engines (longer/shorter mileage, lower/higher rpm limits, etc). Those differences, if present, should be detailed in the vehicle’s owner manual.”

Keep in mind, these are simply guidelines and recommendations. Kiino says there probably won’t be catastrophic consequences if you accidentally accelerate a little too hard or shift a little too late.

“It’s likely that nothing would happen [if you don’t follow the guidelines perfectly], but following the break-in guidelines and proper maintenance are the best ways to ensure the longevity of a vehicle,” he says. “Within the break-in period, the engine may be more susceptible to damage if it is abused.”

Kiino also clarified that failing to follow the conditioning period won’t void your new car’s warranty, but if the car has obviously been abused, that may affect warranty coverage. So go on, drive and enjoy your new car. Just plan some easy miles to get acquainted to each other.

Even though the engine is the biggest concern with regard to breaking in a new car, drivers should also be mindful of the brakes and tires. Their surfaces aren’t yet optimized for performance because they may have a film left over from the manufacturing process. Since tires and brakes both work by creating friction, they’re less efficient if they’re too smooth. So give yourself extra stopping distance for the first couple hundred miles in a new car, or whenever you get new brakes or tires.