Stock HVAC: main distribution duct under glove box to heater box seal...
 

Prepping for a heater core replacement and am scoping out under my dash to see to what degree of molestation (or a lack) that my car has suffered. Everything looks to be there.

One thing I did notice is that the foam seal that goes between the main AC duct under the glove box to the heater box has degraded to nothing. There's still some remnants. It seals to a plastic square shaped adapter on the heater box held in by two screws.

What I don't get it, just how freakin' thick is the foam seal supposed to be? Because there is a good 1" or more gap between the opening on the main AC duct and the adapter on the heater box, and I know it once sealed since you can see the witness mark on the adapter. No wonder I felt barely any air coming out my vents, it's all escaping through that gap and not making it to the main duct to distribute through the rest of the system.

I saw on another post that this missing seal is the main reason behind poor vent output and in my case it definitely makes sense, but why such a huge gap? My duct looks like it's installed correctly (tho the mounting points are broken, but I have a new repro duct on the way), so I don't think it's that. What do people use to replace this seal, because I don't see it for sale anywhere?

Thanks.

i used some foam for home use, kind of a weatherstripping material that had sticky on one side, was a black closed cell foam if i remember right, 3/4-1" thick, looks like its doing great after install ~10 years ago.

Got it. So it's not just me, that Gap is normal lol

I'm doing the same with my car, my whole vent system was missing! I bought a few used pieces to re-install. My car has a vent at the front of the console, but I dont see any ductwork behind it to connect anywhere?

That is the heater duct to blow air to the floor area, no duct for it.

Thank you, I was looking for pieces that didn't exist! I thought it was a functional A/C Vent. I have only had this car about 2 months and keep finding things missing!

Year one sold that foam identical to the GM stuff, when I ordered it they had one of the duct it goes on still on the shelf, I bought it.

Firebird Central thankfully has the repro duct, and it's on it's way to me now. But I can't find the foam, anywhere. I'm still surprised that foam is meant to close such a large gap.

I bought a similar foam at Home Depot for my Q45 airbox intake You could Use that.
Does Year One still have the foam?
Check the white clip on the heater door, those are usually broke.

I just looked. Looks like they don't. :cry: This stuff is at my local Home Depot and it's what I've been thinking about using.

They do have the repro main duct, still, though. It's $77 more there than at Firebird Central, haha. Guess I made the right choice. I guess that specific duct necessitated a reproduction; since it must be break very frequently at the mounting points. Mine is completely broken off from the two mounting points on the bottom, allowing air to escape and essentially causing to just be "suspended" under there.

Let us know how the vent fits. I think it's the same piece another guy did a review on that had all sorts of trouble then gave up and reused his broken original. But I don't know anything about it or se any comparison pics.

The small retainer is #3018715, usually ok when white but starting to get brittle as they turn yellow. A few places sell them in reproduction, white nylon or plastic, likely same part. Likewise, several also sell the aluminium version, tell your friends your build has billet components.