2009 Z4 Break-In Issue

I just bought a 2009 BMW Z4 sDrive35i. The manual states that the break-in period for the car is 1,200 miles and I’m not supposed to go over 100 mph and 4,500 rpm during this period.

Well, I was on the freeway varying speeds from 55 to 65 mph when I tried to overtake this slow car next to me to change lane. When I stepped on the gas(did not floor it), all of a sudden the rpm shot to 5,500 rpm, but the car did not accelerate. I suddenly stepped off the pedal and the engine hung for a second at 5,500 rpm then went down in rpm. I was at 690 miles into the break-in period when this happened.

Did I ruin my engine by going over the 4,500 limit this one time? If so, how can I tell? Or am I just worrying too much?

A few seconds over 4500 shouldn’t be a problem, but I don’t understand what happened. Do you have an automatic transmission? Was it downshifting? Why would the rpms jump but no acceleration?

What they said: “…the break-in period for the car is 1,200 miles and I’m not supposed to go over 100 mph and 4,500 rpm during this period.”

What they meant: Don’t race your car until after the break-in period.

I’m sure that your Z4 is fine.

Your Z4 is fine. You haven’t even stretched the legs of that motor yet. You can sleep soundly.

I’ve been breaking in cars for 40 years. I break 'em in the way I plan to drive them, but without pushing them too much. I pay little attention to the speedo or the RPMs. They run fine for hundreds of thousands of miles. And your motor is capable of far, far more than you’ve subjected it to.

You would not want to see or know the way your car was driven by the various people who had access to your new car before it was delivered to you, Don’t believe for one second that this is the first time your engine has seen 4500+rpm’s.

Does this Z4 have the 7 speed automated manual transmission? You may have inadvertently triggered the launch control system. It may be a software glitch, since it’s under warranty you might want to have the dealer see if there are any firmware updates. But you didn’t hurt anything, you were still well below the redline.

What oldschool says in largely true. When I was selling cars, during the lean months I would volunteer to ferry cars from one dealership to another. While I never “abused” any of the cars, I wasn’t exceedingly easy on them, especially when time was an issue.

Thanks for all your comments. I was just kinda pissed that I was actually following the manual faithfully and then all of sudden this happened. It seems, however, that it doesn’t really matter that it happened.

texases - Can’t explain it. I think the car didn’t accelerate because I stepped off the pedal once I saw it went past 5,000 rpm.

FoDaddy - I do have the 7-speed automatic manual transmission, but I do not believe I accidentally was in launch mode. I was not in sport mode at the time and no checkered flag appeared on my instruments.

If its the same type that I worked with in 2003 (only 6 speed then) BMW called them SMG= Sequencial Manual Gearbox. Sometimes you should take a look at all the parameters that must be met in order for the engine to crank. BMW went to extremes to prevent this vehicle from taking off by itself or injurying someone while they had their head under the hood or in the trunk.

The first 500 miles of break in are the most important.
The first 100 miles are the most most important.
The first mile is the most most most important.

See where I’m going?