2017~2021 Exploding sunroof...wtf?!

:
Ottawa, Ontario
:
17 Mazda 6 GT
I sometimes wonder with the shade closed and the sunroof closed, on a hot sunny day, if the air trapped between the glass and shade doesn't heat up like an oven and cause the glass to break?
It must get really hot in that small space.
 
:
Southwest Ohio
:
'19 CX-5 diesel
When I drive a different car (like a CX9 loaner today) without my nice ceramic window tint I really notice how much heat it blocks out. I have the sunroof tinted with the ceramic film as well. I see two benefits to spending $50 on the sunroof ... keeping it cooler and it does a nice job of holding tempered glass together should it break.

So, A ... maybe help prevent a shattered sunroof (if it's heat related) in the first place
and, B ... maybe keep glass off of me if it does happen.

Pretty good cost/benefit equation on the tint :)
 
:
Cx-9
I sometimes wonder with the shade closed and the sunroof closed, on a hot sunny day, if the air trapped between the glass and shade doesn't heat up like an oven and cause the glass to break?
It must get really hot in that small space.
Thats a very valid point
 
i dont think its the heat, probably a defect in the glass or something else. My cx5 is constantly under 110F in the Arizona summer months. Plus its black. My cover is closed all the time and I dont even use the sunroof.

The good tint idea is a great one. Something I am planning to do as well. The moonroof and even cover get so damn hot in the summer here.

p.s I did have a sunroof shattered on a previous car but a stone actually hit it from the top. What a mess the small particles did...took months to clean the whole car.
 
Last edited:
:
2019 CX-5 Signature Soul Red Crystal Metallic
i dont think its the heat, probably a defect in the glass or something else. My cx5 is constantly under 110F in the Arizona summer months. Plus its black. My cover is closed all the time and I dont even use the sunroof.
With thousands of vehicles made, and this not appearing to be a wide-spread issue, I completely agree with you.

It's likely just a defect in the glass OR.. a stone hit it at some point weakening it slightly.

Go to almost any other car enthusiast site and I'm sure you'll see "exploding sunroof" posts archived there too.
 
:
2014 CX-5 Touring
I sometimes wonder with the shade closed and the sunroof closed, on a hot sunny day, if the air trapped between the glass and shade doesn't heat up like an oven and cause the glass to break?
It must get really hot in that small space.
It's a valid theory, but that inner shade is not air tight. So any expanding hot air can still move to the inside of the car.

My Integra still has the 26 year old original sunroof/moonroof glass on it. I'm more worried about it getting sucked off the track mechanisms at highway speeds than I am the glass exploding. Perhaps it's just "they don't make 'em like they used to"?
 
:
2019 CX-5 GT
I can see Mazda saying "how can we know an object didn't strike it?" It's a valid argument since you were driving when it happened. The hard part is proving it either way. I would assume this would come under comprehensive or windshield on your insurance if they don't accept the warranty claim...
 
:
2019 CX-5 Touring
:
with PP
This same thing happened to me the other day.. my sunroof, moonroof as Mazda refers to it, exploded as we where just driving down the road. No impact on it, nothing around to throw or kick up something on it. Just BOOM. like a M80 went off inside. Luckily the headliner cover was shut so it contained all the tempered shattered glass pieces.

But now the local mazda service rep is telling me Mazda doesn't cover glass under its warranty. So she will have to run it through corporate to see if they will cover it.

@Stickygreen anything I can say or do that you would suggest? Its a 2018 cx-9 with 16k miles. I figured the warranty would cover it.
What was the weather like at the time of the moonroof failed? Was it really hot? Did you have the AC going? Was the moonroof liner pulled back at the time?

I have a hunch [theory] that this is more likely to happen when there is a large delta between the outside temperature and the inside temp.
 

HardRightEdg

US 2020 CX-5 Touring AWD Soul Red
While no consolation for those who have had the exploding sun/moon roof experience, in the great scheme of things they are exceedingly rare given the proliferation of makes, models and years that are suspect, counting in the millions or perhaps 10's of millions of vehicles.

According to Consumer Reports:
  • The first reported incident in the NHTSA data base involved a 1995 model.
  • Between that time and the Consumer Reports story in 2017, there were 859 complaints filed with the NHTSA involving 35 brands and 208 models.
  • Even if you multiply those complaints by a factor of 10 they are still exceedingly rare.
  • Consumer Reports identified a spike in such incidents around 2011-2012 with the proliferation of panoramic sun roofs.
If you throw out the panoramic sun roofs, including the notorious 2012 Hyundai Veloster and Hyundai/Kia in general, the incidents are that much rarer.

Different manufacturers have responded differently: recalls, class action settlements (Hyundai), switching to laminated glass, other changes to manufacturing or design, or flawed glass cause determination. I see no evidence that Mazda has attested to any flaws, alterations or made claims of responsibility. Then again, Mazda has not been high on the hit list (and didn't even register in the 2017 Consumer Reports analysis). It is easy to exagerate the extent of the problem from a small handful of anecdotes. That doesn't mean they didn't tweek something here or there on one generation of one model or another along the way but the fact remains Mazda is low on the list of culprits perhaps specifically because they avoided panoramics in their designs.

So, how does one account for a small handful of incidences among a very large sample size of things that are identical from all appearances? The most likely answer is there is no one single cause but rather multiple factors unique to that particular vehicle, one or more of which may be environmental in the moment.

Perhaps, to take one speculation, Mazda or otherwise, repeated expansions and contractions from heat and cold introduce a weakness in the glass because the frame or glass design or manufacturing did not take that sufficiently into account. But that's not enough with many vehicles so produced with few exploding. Perhaps a flaw was introduced into that particular piece of glass. Or perhaps an unseen and unheard pebble then strikes a weakened piece of glass at a particular angle at a particular temperature while the barometric pressure in the vehicle is at a certain level or some other unique environmental whatnot in the moment as a preciptating cause. If no correlation of causes among the few incidences of a make and model can point to a specific cause or set of causes how are you going to fix it? You can't fix something if you don't know how it gets broken.

Now, Mazda (or some other maker in a similar situation) could switch to laminated glass as a precaution. At least one did, I can't recall which. Maybe it breaks just as often but doesn't blow shards over people and scratch everything in sight. There are a lot of things manufacturers can do differently to resolve a wide range of issues to err on the side of caution but it comes down to frequency, consequence, cost and impact on brand awareness. So far, nobody has been killed or seriously injured by an exploding sun roof in any make or model up through 2018 reports, and the Congressional hearing on the matter came to nothing I can see other than putting manufacturers on notice that they are on the radar if the matter gets worse.

I've owned one convertible and one vehicle with a sun roof. After the novelty wore off, I found I perferred not being wind blown, not having the sun beating on my head, while considering the absurdity of running the climate control with the car open to the outside. But these are matters of personal preference. If I had to buy a sunroof because it came in the car/trim at the price I was targetting I'd consider it a cost of doing business so to speak. That was the case with a 2006 Accord EX-L V6. After trying it a few times because it was there, I'd open it only around once per year just to make sure it was still working and not sticking. But that's me.

When looking at the data in it's entirety, about the only worry to be considered with a sunroof in an existing car or pending purchase might be with a panoramic one. Even then the odds of an incident are very low. In a world full of risks and worries if you care to go looking under rocks for them, this would still be low on the list.

Again, that's no consolation to the rare owners who experienced the problem, suffering panic, minor injuries, inconvenience and cost.
 
Last edited:
:
13' CX-5 and 16' Mazda6 both Touring w/Tech/Bose
My Integra still has the 26 year old original sunroof/moonroof glass on it. I'm more worried about it getting sucked off the track mechanisms at highway speeds than I am the glass exploding. Perhaps it's just "they don't make 'em like they used to"?
Ahh my first sunroof was on a used 1991 CRX si. Wings West body kit with ZC motor. Of course the sunroof worked but only opened (sometimes at least). I had to manually roll it back closed. When I finally got a newer car with sunroof I would always be paranoid whenever its hailing.
 
:
2014 CX-5 Touring
Thankfully my Integra has only been in hail once, and it was only pea sized. I ran outside from my office and quickly moved the car around to the covered drop-off behind my office building at the time. That was like 2004-2005.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Ahh my first sunroof was on a used 1991 CRX si. Wings West body kit with ZC motor. Of course the sunroof worked but only opened (sometimes at least). I had to manually roll it back closed. When I finally got a newer car with sunroof I would always be paranoid whenever its hailing.
To your surprise, tempered moonroof could be stronger than laminated windshield! From my personal experience in 2 hail storms that my CX-5 went through, the windshield got broken twice, but moonroof survived in both hail storms!
 
:
13' CX-5 and 16' Mazda6 both Touring w/Tech/Bose
To your surprise, tempered moonroof could be stronger than laminated windshield! From my personal experience in 2 hail storms that my CX-5 went through, the windshield got broken twice, but moonroof survived in both hail storms!
wow Places like Texas and Missouri has some nasty bouts of hail.
 

yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
wow Places like Texas and Missouri has some nasty bouts of hail.
Yes, indeed! My roof has replaced 3 times in a 5-year span dud to the hail storms, and twice my CX-5 also got hit during the same storms. My insurance has skyrocketed since then!
 
:
Cx-9
What was the weather like at the time of the moonroof failed? Was it really hot? Did you have the AC going? Was the moonroof liner pulled back at the time?

I have a hunch [theory] that this is more likely to happen when there is a large delta between the outside temperature and the inside temp.
Its was between 60°-70°
So it wasn't hot at all. We've in the PNW.
The A/C was not going
The headliner was shut. Thank God or it would have rained tempered glass pieces on us
 
:
2019 CX-5 Touring
:
with PP
Its was between 60°-70°
So it wasn't hot at all. We've in the PNW.
The A/C was not going
The headliner was shut. Thank God or it would have rained tempered glass pieces on us
Interesting.
There goes that theory...
 
usually good tempered glass is strong to some degree on direct impact from the top and is not so strong on its narrow sides.
 
Tempered glass is most fragile on the edges. A blow to the edge and it can shatter. The edges cannot have any contact with metal for instance and must be protected by means of rubber type material. I wonder if the issue has to do with how the glass in affixed to the frame and not allowing sufficient ”float” to the glass. I have not heard of spontaneous breakage where tempered is used in side glass that is frameless and vertical.
 
Last edited:
Top