Headliner fabric has a foam backing and the foam is disintegrating due to time and heat and humidity. Best to get it re-upholstered. I bought new headliner fabric for $30 on Amazon and had it glued on at a shop but you could probably do it yourself with the right spray adhesive. It's a lot of work getting the headliner out and many pillar clips broke on my car but I repaired them with epoxy.

 

I dread the time to pull liner out of the car as this is the hardest part. Any chance in removing part of the side pieces to get access and spraying the adhesive into the space?

 

What I've heard from others is that the old fabric with disintegrating foam has got to go... but you could give it a try and see what happens.

 

I'll have a closer look on the weekend. Might try and pull the rear hatch moulding off first as this allows access to the worst part of sagging headliner.
Ultimately, I believe I will need to pull whole thing out, clean up and re-attach (or replace). Still rainy winter conditions here so not the best for working outside.

Thanks for the help.

 

Also check on top of the headliner, mine was wet from water leaking past the useless car-phone antenna. The rubber at the base of the antenna rots and cracks and water was leaking inside and I didn't even realize it until i looked inside. I threw out the useless car phone antenna and plugged the hole with an antenna delete plug. Also if you do take out the headliner and lights that would be a great time to upgrade your bulbs to LED's .

 

No other holes in roof or water leakage. Already replaced lights with LEDs as was one of first mods.
Think it may have failed as we get quite hot conditions in summer and car lives outside. Having the roof wrapped in black may have accelerated deterioration. Not all of headliner has failed just from drivers side back. Didn't even notice it until recent trip was driving and I reached into back seat area to grab something.