Trunk seal - to glue or not to glue?
 

Hi all. I'm replacing the door seals and trunk seal on my '89 3.2 coupe - not least because I've been inspired by previous posters' promises of how it'll make my car feel like new, cutting down road and wind noise. (Turns out to be true; although it now exaggerates the rattles inside).
I found great advice re not needing to glue the door seals - they're shaped such that they "plug" perfectly into the channels.
When it comes to the trunk seal, though, the choice isn't as clear. The seal (Porsche genuine) sits in the channel pretty well perfectly, although at the top corners (i.e. near trunk hinges) it sits maybe 0.5-1mm shy of being flush against the side of the channel. My question is: it doesn't need gluing (3M Weatherseal) to keep it in place - but if I don't, isn't there a danger of water getting in and being trapped under the seal?
Am I better off trying to remove this danger by gluing the seal to the channel all the way around - or not gluing, and periodically lifting out the seal and checking for water?

I think that I would glue it and not have to periodically remove it to check for water. 3M is the only way to go if you do glue it.
Body shop used 3M on mine after the repaint and I have no issues.

If you haven't already a new windshield seal will also help cut down on wind noise. I've heard it said many times (and it's what I did) only use a genuine Porsche seal.

74 with serious rust perforation under trunk seal
 

i rolled my dads 74 outside toput my nephews truck up for some brake work and it rained. after rolling it back inside, i checked inside the car and there was wet carpet,passenger side front. windows were up and doors fully closed.
the right rear trunk gutter had some bubbled paint, i felt under the gutter and it was rusty and wet. apparently, his shop had liberally applied some adhesive goo to hold back the tide, but the tin worm prevailed. I could stick two fingers through holes in bith corners.
About 15 years ago, he had the car repainted and i cannot see a shop that did such nice work just gluing in a new weatherstrip over that rust.

i think this emphasized to me the importance of keeping the paint intact as a protector against rust, so, while scraping off the old weatherstrip and GOO, be careful to not pierce the paint. i would not trust the glue to be completely water tight.

i have a restoraation design cowel panel and am waiting for my friend to section out the gutter.

i will be gluing in the new seal.
chris

Do not use "silicone" sealant to hold the seal. It often has an etching additive to aid adhesion. This will F up your paint under the seal.
PO of my car had the seal replaced and they used this crap. Only rust found on my car during bare metal repaint was under the seal. Grinding, acid etching, rinse, prime, fill added some $$ to my repaint costs.

Thanks to all. Comments (particularly Chris’s) have led me to a compromise: there is about an inch-long strip of bubbled paint in the left-hand (longitudinal) channel, near the windscreen end. Nothing wet or crumbly or sinister underneath, but I’d be silly to leave it there. I have another small panel/paint job to be done in the next few months, so will hold off gluing till that’s done. Result!