I see lots of post re window regulators, but this is the back facing window, above the trunk.
The adhesive has failed, the window is sliding down into the trunk lid, leaving an open gap at the top!
With all the windows closed, when you close the driver door the back window pops up off the frame!

Its been in the upper 90's this week, and the mid 80's today when it separated.

2001 A4 1.8TQ.

Has anyone else seen or heard of this?

 

Never, ever heard of that. Those are glued in with a urethane adhesive. Those of us who have swapped out glass will tell you it takes a lot of cutting with knives and wire to get that stuff out of there.

You'd better get this fixed. Not going to heal itself. And unless you have some experience, might as well take it to a glass shop.

 

Definitely get it done professionally. You don't want to damage the rear window, defogger strips.

 

Good point, it slid down about an inch, the defrost connection may already be trashed.

 

Yes, I have visions of it lifting off and flying away.

I removed and replaced fixed windows in the back 'barn doors' of a GMC Suburban when painted it. Had to cut the adhesive with piano wire.

I think this will have to go to the glass guy/shop, its way bigger than the two little windows in the Suburban!

 

My guess would be it was replaced once and the wrong type adhesive was used. In all the years I've worked on cars, have NEVER seen that happen with bonded glass.

 

Yes, I wondered about that. I've had it for about 3 years, so it is possible that it been replaced and not properly installed. Let's hope for the sake of B5'ers everywhere this is a one-off issue.

 

Here are photos showing the rear window separation.
It slid down until it is resting on the trunk.

 

Never ever seen that. Couldn't have come from the factory that way.

 

Judging by the way the glass slid and the appearance of the urethane, it was the wrong stuff. The correct glass setting adhesive melts at something like 250*(f) and even then, would probably still keep the glass from sliding down.

You may be OK with the defroster. the connecting wires on either side of the glass are long enough. Otherwise, only need to glue the terminals back to the grid of they came off. The glass guy should have the stuff to do that in his van when he (or she) comes to fix the window.