Rear window 1998 Porsche 996 cracked

[jo996]

To my horror I discovered that the rear window is my 996 was cracked. I have no idea what has happened. The car is not used during the winter months and is parked in the garage at a constant temperature. No one has touched the car and nothing has fallen on the window. 

I have already contacted my Porsche dealer asking them what could have caused the window to crack spontaneously. As they had never heard of this having happened before they could not give me an answer.

 

My Porsche dealer hires an outside firm to repair windows and as I do not want to drive the car without a rear window the repair will be done at my place. I have to rely on the expertise of the person who is coming to replace the window. I would, however, Very much like to know how he is supposed to install the new window.

 

I take it that Porsche has guidelines for repairing the rear window. For instance, I can well imagine that part of the interior trim has to be removed. Does anyone know what these guidelines are? Does anyone have an idea what might have caused the window to break spontaneously? Is my case a one-off or has this happened more often?

 

Jo996 the Netherlands

[jo996]

Had it been a convertible yes, but it is a coupe. As yet it remains a mystery. It must have been caused by tension in the window. There are stories on the Internet telling about Volkswagens which have windows that break spontaneously. 

 

jo996

[Ahsai]

In case yours a coupe, the general steps are shown in this video (video is for front windshield but it's the same concept). Since the shop is used by your Porsche dealer, it should be reasonably good but you could also check for reviews from others.

 

 

[Ahsai]

Btw, it's indeed strange. It's not a common failure though. The glass is not butting up against the frame and it's insulated by flexible sealant so I can't see how expansion can make the glass crack. Any previous body work around that area?

[jo996]

No previous body work carried out. Nothing has fallen on the window. No one has touched it. I don’t know but does the sealant lose (part of) its flexibility over the course of time. I’ll ask the person who is going to replace the window.

 

I had the front window replaced a few years ago. I think replacing the rear window is more difficult than replacing the front window. I could, of course, be mistaken. I have removed most of the window, but around the edges the sealant holds a lot of glass splinters. I’m afraid some/a lot of them are going to end up in all sorts of openings of the body. Don’t want that to happen, of course. 

[Ahsai]

Yes and a good tech will bring a vacuum with him/her to clean up any broken bits. It's just part of the job.