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Old 11-11-2011, 07:57 PM   #27
Two wheels or four
Join Date: Sep 2011
Location: Windsor
Posts: 10
I dropped the car off at BMW Toronto last Saturday morning and they were very good to deal with. They told me they would report the incident to BMW Canada on Monday to see if it would be repaired as a warranty item.

On Monday morning, I composed an email using some of the relevant links uncovered by maXbimmer Forum members, and sent it to the Assistant Service Manager:


Thanks for taking the time to get my car booked in for service on Saturday without an appointment. Enterprise Rental Car was fast and courteous and they gave me a rental car at your discount rate.

In regards to my damaged car, I think that BMW should fix the defective sunroof under warranty. Here is my rational:

1. There was no obvious external cause before the explosion. No bump, no rock, no pothole, it was a normal Friday afternoon drive home from work. To recap, I was driving the car down the Gardiner Expressway just after 5:00 p.m. on Friday November 4, 2011 when the sunroof exploded over my head. I was going about 90kph, the sunroof and windows were closed, there was no overpass overhead, it was 9 degrees celsius outside, and I did not hit a bump or experience anything unusual just before it happened.

2. The physics of a rock hit don't work. Here is a video showing another 2010 BMW 328i with an exploding sunroof. The professor in the video explains that the angle and location of the sunroof do not allow a rock to hit it hard enough to break unless the glass is defective.

From the news report: 7 On Your Side then discussed this incident with Tarek Zohdi, a professor of mechanical engineering at UC Berkeley. He calculated a rock lofted into the air by a vehicle tire would reach a height of 10-15 feet and would have to come down at 70-80 miles an hour to break the sunroof.
"There is not a chance in the world that an unintentional rock that is lofted by a vehicle would ever break a sunroof panel," Zohdi said.

Zohdi says the maximum velocity of a rock coming down would be 25 miles an hour, well short of the needed 70 miles an hour. He said it is more likely the sunroof broke due to the stress caused by changes in temperatures or from fatigue.

"In both cases I would say in my opinion the car manufacturer has the problem; basically it's a manufacturers defect," Zohdi said.

3. There are a number of similar occurrences to other BMW's. You told me that you had only ever seen it with a seven series but here are links to the first five that I found for three series BMW's:

The BMW in the video above is not included in this list.

In summary, I'd like this fixed under warranty because I think that the sunroof glass was defective in my car. BMW will be able to get trace data from their supplier and I expect that there are other cars build with the same glass batch as mine that have had a similar defect. A new car should simply not experience this type of component failure.

If BMW does not agree, I would like a contact there that I can talk to.

Thank you again for your assistance on Saturday.

Dave Black

Here are some photos of my car right after I pulled over on Lakeshore Blvd. I think you'll agree that the car and the incident are almost identical to the exploding sunroof in the video above.
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