Exploding Sun Roof on 2020 CX-5 Grand Touring

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2020 Mazda CX-5
On Oct. 6, 2020, while driving North on I-95 in Virginia, nearing Exit 133, our sun roof suddenly and spontaneously exploded outward. We were traveling at about 50-60 MPH and slowing to leave the highway at Exit 133. Our car is a 2020 Mazda CX-5, purchased in July 2020. We have less than 4,000 miles on the car. There is NO evidence that our car was struck by any object that might have caused the sun roof to explode outward. There are no other scratches or dents on our virtually brand new car. Because the sun shade was closed, no shattered glass entered our vehicle. We were fortunate to have not lost control of our vehicle and crashed. The spontaneous sun roof explosion was very loud and it shook the car causing a momentary loss of control. This is probably a Mazda defect.
 
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2019 CX-5 Signature
Not a Mazda defect. It actually occurs more often than you would think.
 

rsvinylgraphics

2008.5 MGM MS3
Contributor
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2008.5 MS3
Actually it is a very common occurrence on not just Mazda vehicles but many other manufacturers vehicles.
Do a google search and you will see what I am talking about.
 

sm1ke

Work In Progress..
Moderator
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Canada
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'18 CX-9 Signature
No pictures of the damage?
Have you contacted the dealership you bought the car from, or Mazda North America Operations?
It doesn't appear to be specific to Mazda as I've read about this issue occurring with many different brands, from Hyundai/KIA to VW and now Mazda.
 

Antoine

Administrator
Sorry to hear...I wonder if this is a case where several automotive manufacturers such as Mazda utilize the same supplier?
 

sm1ke

Work In Progress..
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Canada
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'18 CX-9 Signature
So I combed the forum and found the following related threads specific to Mazda models:

2019 CX-5 - Happened at around 70mph.

2015 CX-5 - Occurred on the highway, speed not clarified. Also in this thread, someone reported the sunroof breaking on their 2016 CX-5 while it was parked overnight.

2010 Mazda CX-7 - Happened at highway speeds. Also in this thread, another user reports the same issue on their 2012 Mazda 3, and a few more users report the same issue on their vehicles (2015 CX-9, 2012 CX-9, 2010 CX-9, 2015 CX-5, 2012 CX-9).

2014 CX-5 - Highway speeds.


I didn't go all the way back to the start of the forum, so there may be more reports, but it seems as though it's been happening much more frequently now than it has in the past.
 
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2010 CX-9 GT
This can be filed in the "sh*t happens" category. It's made of tempered glass, so there's an enormous amount of internal stress in the glass just sitting there. Any small defect on the edge or damage due to an impact can cause it to shatter at a seemingly random time.

Take it to the dealer, get it replaced, and move on.
 
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2020 Mazda CX-5
Thanks for all the thoughtful replies. I guess we, and apparently many others, were lucky enough to not have crashed our vehicles and have survived the incident. We were in very heavy traffic and on a tall bridge that was being expanded with additional lanes when the incident happened. Fortunately, we maintained control of our vehicle.

I too have searched the Internet for other examples of this problem and acknowledge that it is not unique to Mazda. Perhaps it is up to the National Highway Traffic Safety Administration to take remedial action on all automobile makers.

For the curious, I have attached two images of the "exploded" sun roof. The picture taken outdoors has a lot of reflected sky and a nearby tree in it, but the hole can still be easily identified. The picture in our garage may show the hole more clearly.
 

Attachments

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2020 Mazda CX-5
I have been in frequent communication with both my local dealer and Mazda USA. Neither acknowledges any responsibility for the damaged sunroof and neither is willing to cover the repair costs. My car had 1,992 miles on it, and was only 3 months old, when the sunroof failed.

Curiously, front wind shields and side windows don't seem to fail spontaneously. Perhaps sunroofs need to be made of different materials.

So, whose "fault" is it and who should pay to cover the repair? Why am I stuck with the bills when the failed sunroof was clearly a manufacturer's problem?
 

sm1ke

Work In Progress..
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Canada
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'18 CX-9 Signature
I think that's the problem, nobody can prove that the manufacturer or the owner are at fault. They can't even determine the root cause of the problem. The whole situation makes it easy for everyone to wash their hands of it and say "not my problem", which is a shame.

File a complaint with the BBB and the NHTSA against Mazda. Get the sunroof repaired and hold on to the invoice in case they're able to identify a cause in the future and you can get your money back.
 
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2010 CX-9 GT
Frankly, Mazda not assuming any responsibility is no surprise to me. They claim to want to be a premium brand but don't treat their customers any better than hyundai or chevrolet.

Your next step could be insurance. They will cover a new windshield, file a claim and see if they will cover this.
 
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2010 CX-9 GT
Mazda also picked up the tab for a CX-9 sunroof:


Maybe you should PM one or both of these folks and see if they have any advice.
 
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2014 Mazda3 S GT auto, 2008 MX5 6-speed
I've never seen a post about this happening to a Mazda3 owner. Maybe your sunroofs are large enough so that the extra stress from high temperature conditions is causing the excitement.
 
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2014 Mazda3 S GT auto, 2008 MX5 6-speed
Now that I think about it, cold weather may be more likely to cause the glass to explode. The CTE (Coefficient of Thermal Expansion) is higher for the surrounding steel (10.8-12.5) than it is for the glass (4.0 - 9.0) in 10 to the minus 6 meters per meter - degrees C.
 
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2010 CX-9 GT
The Consumer Reports article states that this happens every month of the year all over the world. It seems unlikely that temperature is a primary cause given the failures aren't correlated to climate or season.
 
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2014 Mazda3 S GT auto, 2008 MX5 6-speed
But really, something has to change, otherwise the glass would never explode. Something is causing it to be stressed. (change in temperature between inside and outside the glass?)
 
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2010 CX-9 GT
It is tempered glass. The glass itself is always under stress. All it needs is something to disturb the equilibrium between the surface (under compression) and the middle (under tension). This can be caused by impurities in the glass itself, so nothing need change for a piece of tempered glass to shatter.
 
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2014 Mazda3 S GT auto, 2008 MX5 6-speed
What could cause a sunroof to explode or shatter?
CarComplaints.com contacted four of the top university mechanical engineering professors and asked that very question. All agreed the problem could be found in the glass itself, not necessarily how it was installed in the vehicle. In fact, all types of glass products can explode, including ovenware, patio tables, even glass balconies. It’s occurred for years and the problem has grown in vehicles because more cars come standard with a sunroof/moonroof, something that was once considered a luxury option.

A sunroof is made with tempered glass that is designed to break into small pieces for safety. Any imperfection in the glass--whether caused by a bad batch of glass or a scratch from a rock--can cause the glass to shatter when under pressure. The pressure might come from the vehicle itself because every vehicle is more airtight than ever.

Because a glass sunroof is under a lot of compression, air pressure or temperature changes can all contribute to pressure on the glass. All it takes is one microscopic imperfection and time to allow the problem to reach a level where the glass explodes.

Previous unrelated investigations found nickel sulfide crystals in shattered glass. These crystals can grow and if their growth is in the correct direction, the glass will shatter from the pressure.
 

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