Do new cars need to be 'broken in'?

I seem to remember that years ago, it was recommended that a new car should not be run at the same speed for long. A combo of city/highway driving is best for the first X amount of miles to ‘break it in’.

While this seems to make sense, I wonder if it still applies?

I’m asking because my Wife will be getting a new car in (hopefully) early September. Near the end of September we embark on a 4000 mile road trip. We would like to take the new car, but it may have only 500 miles on it.

The option is to take my car. Twelve years old with 200,000 miles on it. Worse gas mileage and not quite as many accoutrements.

No. The car break-in issue was from back in the day when manufacturing processes, metallurgy and related machine tolerances called for it. That has not been the case for at least the past 15-20 years.

Second the no. Definitely take the new car.

Nah. There’s no market for factory car radios anymore.

Wait, what?

Check your owner’s manual. Any break-in recommendations are going to be listed in there. It’s different for each car, but many (most? all? I have no data, just anecdotes) new cars will still have some recommendation, or will spell out that no break-in activities are required.

In general though, it’s unlikely that the break-in periods are necessary anymore, and even less likely that anyone would void your warranty for not following it.

Even if there were a justification for breaking in a modern car (the latest iterations I’ve heard were"give the brake pads a chance to set" and “see if any of the electronics modules are faulty before you get stuck far away from home”), 500 miles should be more than enough.

Thanks all. That’s pretty much what I thought (but will check the owners manual). This will relieve my Wife as well.

When I bought my first new car, in '91, the dealer noted a recommended break-in period, the primary guidance being to not drive the car at the exact same speed for an extended period of time, for the first 500 miles or so.

I’ve bought three new cars since then, and have not gotten, nor read, any specific break-in recommendations on any of them.

One of the main reasons for the break in period was to seat the rings. I recall one road test of an MG in the 1960s where they took a short trip before the testing began to break it in. They made a try at top speed after the trip. Later in the day when the engine had completely cooled they made another run and after a brief time at top speed they backed off the throttle to pull a bit of oil up using engine vacuum and nailed it. They said the short trip combined with the cool off had resulted in the perfect break in and top speed went up 5 mph.

With micro polished bores, precise tolerances and ring coatings there is no need to break them in.


Looks like you don’t want to do anything very extreme in your first 500-1000 miles, and definitely not full-throttle operation.

I’d read the manual and do what it says.

Here’s what my 13 year old pickup (2005 Dodge Dakota) has to say:

And here’s what my wife’s '12 VW Passat manual has to say:

Yeah, we’ll read the manual.

The ~15 mile trip to my wife’s office is 50mph 2 lane mountain highway. So it goes over a pass, and has lots of 10mph switchbacks as well as straight aways. Seems like it would a pretty good road for break in. Also, it doesn’t get very hot where we live if that matters. Temps in Sept will be about 30F in the morning to maaaaybe 70F in the afternoon.

Break in: Follow the manual.

Some break-in periods consider things other than engine internals, being that tires, breaks, belts and hoses are all new, it’d be nice if we didn’t forget about a few cycles doing them well.

Heck, some tires aren’t broken in for 100 miles and some could take upwards of 500.

Metals need heat cycles and so do things like gaskets and modern liquid gaskets.

Transmissions have moving parts, too.

Follow the manual.

I second (or third, fourth etc :slight_smile: ) to follow the manufacturer’s recommendation. But break in is real and a fairly big deal for some cars. It’s not correct to say it’s a thing of the past.

For a BMW M2:
“Up to 1,200 miles/2,000 km
Drive at varying engine and road speeds, but do not exceed 5,500 rpm and 106 mph/170 km/h.
Avoid full load or kickdown under all circumstances.
At 1,200 miles/2,000 km
Have drive-in checkup maintenance performed.
From 1,200 miles/2,000 km to 3,100 miles/5,000 km
The engine and road speed can gradually be increased to a constant speed of 137 mph/220 km/h.
Use the maximum speed of 155 mph/250 km/h only briefly, for instance when passing.”

I get a chuckle out of that last line. But anyway note you’ve actually got to get a maintenance check at 1,200 miles. And from I’ve heard directly from techs that’s not to be skipped: they replace special break-in fluids and there will be metal shavings from the break-in especially in the car’s limited slip differential. That’s perhaps a slightly extreme car, but not a very extreme car.

Owners of cars in that general category debate on the web whether you should do things like try to fairly heavily load the car’s engine, though not flooring it as BMW prohibits. Some say doing that will materially help the rings seat properly as opposed to driving very light footed in the break in period. But as you can see BMW doesn’t recommend anything beyond varying speed, limiting speed/rpm, and no flooring/kick down (latter means pushing the gas pedal beyond the first detente on the ‘floor’).

Also agree to follow the manufacturers recommendation. It is still sound advice to follow on newer vehicles as well even when they do not require it (remember most newer vehicle/manufacturers say you never have to change transmission fluid :smack:).

As I said, we will follow the manual.

Corry, hadn’t thought about a possible maintenance check by a dealer. Since this is a 4000 mile road trip, it might be the deal breaker to take the new car. :frowning:

Thanks all, I’m out of here until Monday. My internet is down at home.

It’s unusual. Not even BMW’s generally, just ‘M’ division sports cars. Maybe some other high performance cars but it’s relatively unusual.

When I was younger we toured a GM engine factory in our city. They put the engines though a good thorough wringing after assembly even before they got into a car. I wouldn’t be afraid to floor it on a new engine occasionally.

I took my brand new (3 day old) 2011 Toyota Scion Xb for a 1300 mile road trip to Carrizozo, NM for some cherry cider and to see the VLA. I went there-and-back-again in 22.5 hours. I’m still driving it. I still get 28.5 mpg, just like the EPA said when I bought it.

A lot of cars of that era had a similar requirement. It’s not a “break-in” period as much as it’s a “give the engine computer some varied conditions so it can figure out how to set itself for maximum performance” period. If you disconnected the battery or in any other way managed to get the engine computer to lose its settings, you needed to start all over with varied driving conditions so that the computer could re-learn its optimum settings.