Glass panel between sunroof and windshield cracking

[Ggpe]

Wife and I heard the typical sound of a pebble striking the windshield. A careful inspection did not reveal any chipping or cracking.

Fast forward a few weeks. I am washing the car and noticed what appeared to be matallic paint reflections coming from the black roof panel. When I rubbed my finger over the panel, I cut my finger. ‘Uh oh!, I said!

Turns out the roof panel between the sunroof and the windshield is made of untempered glass, and that sound we heard weeks before was when a pepple hit that panel!

Price to replace… $1,430 plus tax!!

I found out Genesis had sunroof glass failure problem and extended the warrantees on the sunroof for up to 2017 models.

Question I have is am I the only one that did not know that panel was glass? It looked like the rest of the body to us.

Being fair, Genesis is looking into this problem and it will be taken care of by them or our insurance. Just wondering why glass panelling?

 

[FastEddie]

Wife and I heard the typical sound of a pebble striking the windshield. A careful inspection did not reveal any chipping or cracking.

Fast forward a few weeks. I am washing the car and noticed what appeared to be matallic paint reflections coming from the black roof panel. When I rubbed my finger over the panel, I cut my finger. ‘Uh oh!, I said!

Turns out the roof panel between the sunroof and the windshield is made of untempered glass, and that sound we heard weeks before was when a pepple hit that panel!

Price to replace… $1,430 plus tax!!

I found out Genesis had sunroof glass failure problem and extended the warrantees on the sunroof for up to 2017 models.

Question I have is am I the only one that did not know that panel was glass? It looked like the rest of the body to us.

Being fair, Genesis is looking into this problem and it will be taken care of by them or our insurance. Just wondering why glass panelling?

It was to match the glass pano roof.

 

[Ggpe]

It was to match the glass pano roof.

So, why isn’t the entire roof glass if matching was a objective. The metal roof behind the sunroof matches exactly. My problem is the difference between a pebble causing a minor chip in paint versus a $1,400 repair. What was the real purpose of this glass panel on the roof? If I knew its purpose, maybe I could stop thinking about it. It makes no logical sense. Genesis said they will get back with me. I will let you know what they said. I suspect it has something to do with the sunroof shattering glass problem they had earlier. I am not an engineer, but having glass panelling on the leading edge of car seems strange. Lol!

Like I said, We love our Genesis! They did call us back, and said they were still looking into it.

 

[Abuschauffeur]

This is what is known as a Spandrel Spandrel. Spandrel Panels are infill panels to cover something up of what is behind. Often, but not always, they are used to cover something unsightly that lies behind. If the panel is made of glass to match the surroundings, (other materials can be used) what lies behind then is painted dark, almost always black, to stop reflections shining through. When the sun belts down on the spandrel panel the black backing absorbs heat and it can get very hot.

To me your breakage looks typically like glass that was tempered. When spandrel panels are used in buildings they are almost always tempered because when they break they must shatter into small granules. (Panels can also be laminated). I do not think plain annealed glass is ever used in the car industry unless it is laminated. And your breakage does not look like laminated glass.

When tempered glass spontaneously shatters it is always because of Nickel Sulfide inclusions (often found in cheap glass) or if the glass is fitted in such a way that it is under tension. Add to this enormous heat build up, the glass will expend, it cant go anywhere if it is already fitted under tension or if indeed NiS is present... bingo !

In your case the glass may have been at the edge ready to break and all it took was for a small impact to push it over the edge. Typically of tempered (toughened) glass.

All of this is of course speculation.

 

[Ggpe]

This is what is known as a Spandrel Spandrel. Spandrel Panels are infill panels to cover something up of what is behind. Often, but not always, they are used to cover something unsightly that lies behind. If the panel is made of glass to match the surroundings, (other materials can be used) what lies behind then is painted dark, almost always black, to stop reflections shining through. When the sun belts down on the spandrel panel the black backing absorbs heat and it can get very hot.

To me your breakage looks typically like glass that was tempered. When spandrel panels are used in buildings they are almost always tempered because when they break they must shatter into small granules. (Panels can also be laminated). I do not think plain annealed glass is ever used in the car industry unless it is laminated. And your breakage does not look like laminated glass.

When tempered glass spontaneously shatters it is always because of Nickel Sulfide inclusions (often found in cheap glass) or if the glass is fitted in such a way that it is under tension. Add to this enormous heat build up, the glass will expend, it cant go anywhere if it is already fitted under tension or if indeed NiS is present... bingo !

In your case the glass may have been at the edge ready to break and all it took was for a small impact to push it over the edge. Typically of tempered (toughened) glass.

All of this is of course speculation.

This is a great explanation of what happened regarding the ‘why and how’ the glass cracked. Thank you! I just want to understand ‘why’ Genesis engineered a seemingly unpurposed expensive glass panel on the leading edge of their cars.

Having spent a lifetime as a maintenance manager, I cannot perceive any advantage to using any unnecessary glass on the leading edge of an automobile, other than the obvious: windshield, lights, etc.

Thank you for your explanation! It was very informative.

 

[Abuschauffeur]

...‘why’ Genesis engineered a seemingly unpurposed expensive glass panel on the leading edge...

Why it is there has a reason, no doubt. In my mind there are two cases to consider.
1) There is something fitted which is needed for the operation of the sunroof.
2) The glass roof was too problematic to install all the way to the front and not introducing cabin flex.

While both cases are good candidates I think No. 2) is the more plausible one. But it is also possible both share equal billing.

Since this space has to be covered I think the good people at Genesis thought it will look better with all glass front to back rather than introducing another material. If the windscreen can hold up to every day driving there should be no reason this panel will not.

 

[Ggpe]

Why it is there has a reason, no doubt. In my mind there are two cases to consider.
1) There is something fitted which is needed for the operation of the sunroof.
2) The glass roof was too problematic to install all the way to the front and not introducing cabin flex.

While both cases are good candidates I think No. 2) is the more plausible one. But it is also possible both share equal billing.

Since this space has to be covered I think the good people at Genesis thought it will look better with all glass front to back rather than introducing another material. If the windscreen can hold up to every day driving there should be no reason this panel will not.

There is no difference in the appearance of this panel and the non-glass roof behind the sunroof. My thinking, after a little research, is that Genesis changed the sunroof design in 2018 due to shattering, and extending the sunroof warrantee on pre-2018 models. Unfortunately, perhaps, their ‘fix’ did not address the glass panel that is not part of the moveable sunroof. I am not an engineer, so if there are other cars with a glass panel in front of their sunroofs, then there must becgood reason.

I hope to hear something soon. Lol! I am not an engineer! I appreciate your insights! Thank you very much!

 

[Abuschauffeur]

I just had another thought, if the satnav satellite areal is located there steel would not be any good.

 

[Ggpe]

I just had another thought, if the satnav satellite areal is located there steel would not be any good.

That is something I never gave any thought to. I will need to check into that! Do you think all cars with satnav have this glass panel or similar?

 

[rmod]

That is something I never gave any thought to. I will need to check into that! Do you think all cars with satnav have this glass panel or similar?

The satellite antennas are in the "shark fin" on the roof.

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[mrcleeaan]

Shine a light on it at night. You can see what's underneath in the middle. Must be there for a reason or could be just for aesthetic reasons to match the sunroof.

 

[leowaner]

I had a similar event than yours on my 2008 LS460L.... a thousand miles from home. A rock came off of a pickup I was following, early AM on I-80 in the mountains, the only other truck within sight. The sun roof glass panel exploded and scared the sh*t out of me. Luckily the inside shade was pulled... as I started to open to look and a shower of pebbled glass came down everywhere. And yes it was expensive to fix with Lexus glass. And yes again, it's not windshield glass in these roof panels, nor does the aftermarket make these units [for me at least]. I would take the small finger cut over an explosion, you where kinda lucky? I had to Gorilla tape the whole opening and it still howled and whistled some.... it was atrociously loud and thumping with that glass completely broken out as it cycled through compressing the cabin and releasing the air pressure... you could see where the rock hit... the very edge of the plastic/rubber liner around the glass, and, of course, the glass.

 

[Ggpe]

Thanks for sharing. Your experience seems identical to the 2017 and earlier Genesis sunroof problem. They redesigned and extended the sunroof warrantee on all pre-2018 models.

If the sunroof glass composition was changed then, one would think all the glass components using the same failing glass design would have been changed. If not, why not? Maybe this is an updated design. The glass is shattered, but not breaking apart. It almost looks cool, hut not really! Lol!

Thanks

 

[Ggpe]

Shine a light on it at night. You can see what's underneath in the middle. Must be there for a reason or could be just for aesthetic reasons to match the sunroof.

I will definitely do that tonight! Thanks!

 

[rmod]

I will definitely do that tonight! Thanks!

The "front glass" (that is what they call it in the service manual) is the cover for the screws for the "Wide Sunroof". It is glued into place. From the looks of it, it is made of glass for either esthetics or ease of installation (glue in from the outside v/s screwing it in from inside).

 

[Ggpe]

The "front glass" (that is what they call it in the service manual) is the cover for the screws for the "Wide Sunroof". It is glued into place. From the looks of it, it is made of glass for either esthetics or ease of installation (glue in from the outside v/s screwing it in from inside).

Well, you made a clear, logical case for why there is a panel there. The aft portion of the roof is metal, and matches beautifully. Why wouldn’t the same be ‘glued’ in for the front panel? I assune all sunroofs have a panel/strip in front. Do you know if glass is used elsewhere in the industry?

 

[rmod]

Well, you made a clear, logical case for why there is a panel there. The aft portion of the roof is metal, and matches beautifully. Why wouldn’t the same be ‘glued’ in for the front panel? I assune all sunroofs have a panel/strip in front. Do you know if glass is used elsewhere in the industry

I am not aware of any other cars that have this glass...but from the pictures online I think Sonata, K5 and Stinger have it (I am sure if you search online you will find some others as well)....and some of the newer EV's do the entire roof with glass (Tesla, Mach-E etc.)

 

[Abuschauffeur]

The aft portion of the roof is metal...

Are you sure ?
The back panel in my G80 (not G70 though) is glass.
I would think glass was chosen for a reason. A piece of sheet metal may not be easier or more cost effective to install. A piece of sheet metal may also be more difficult to break in (remove) for repair of what lies behind. Bit far fetched, still a possibility.

Glass will also be a better sound attenuator. To achieve this a sheet of metal needs to have some sound deadening material sprayed or glued to it. Otherwise during rain or hail it will ring like a drum.

On closer examination, (on my vehicle) I can see a small part of the panel's underside is screen printed and the rest is clear and reveals black painted matte metal a short distance below.

From this I deduce the following:
1) The small part which is screenprinted hides, most likely, the roof mechanism. And everything mechanical needs access for servicing/repair. I am sure glass is easier to remove by just breaking it and remove fragments from the edges with special solvents. I know this from the building industry. But, this is only an assumption on my behalf.

2) The matte painted steel I can see through the “not printed„ sections of the glass is the stiffening brace to stop cabin flex. (As is the middle section of the roof.)

Why is this glass panel not painted black all the way on the underside I hear you say ?
Glass, and particularly toughened glass, does not play nicely when this is the case. Heat buildup will be enormous, expansion also and in case of tight fitment requirements to stop leakage this would not be good.

I have, I think, exhausted all possibilities and leave it at that.

 

[jjsC6]

All these explanations as if doing it the way sunroofs have been installed in a gazillion cars for decades hasn’t been sufficient. Seems to me it is all about aesthetics.

 

[Ggpe]

Are you sure ?
The back panel in my G80 (not G70 though) is glass.
I would think glass was chosen for a reason. A piece of sheet metal may not be easier or more cost effective to install. A piece of sheet metal may also be more difficult to break in (remove) for repair of what lies behind. Bit far fetched, still a possibility.

Glass will also be a better sound attenuator. To achieve this a sheet of metal needs to have some sound deadening material sprayed or glued to it. Otherwise during rain or hail it will ring like a drum.

On closer examination, (on my vehicle) I can see a small part of the panel's underside is screen printed and the rest is clear and reveals black painted matte metal a short distance below.

From this I deduce the following:
1) The small part which is screenprinted hides, most likely, the roof mechanism. And everything mechanical needs access for servicing/repair. I am sure glass is easier to remove by just breaking it and remove fragments from the edges with special solvents. I know this from the building industry. But, this is only an assumption on my behalf.

2) The matte painted steel I can see through the “not printed„ sections of the glass is the stiffening brace to stop cabin flex. (As is the middle section of the roof.)

Why is this glass panel not painted black all the way on the underside I hear you say ?
Glass, and particularly toughened glass, does not play nicely when this is the case. Heat buildup will be enormous, expansion also and in case of tight fitment requirements to stop leakage this would not be good.

I have, I think, exhausted all possibilities and leave it at that.

All these explanations as if doing it the way sunroofs have been installed in a gazillion cars for decades hasn’t been sufficient. Seems to me it is all about aesthetics.

I can agree with you! I just went out with a light and found out the forward roof strips above each front door is also glass… but the rear half of the roof is not! Lol! I have a better picture forming in my mind as to why this is.
Thank you!