What is used to seal the evaporator case to the firewall, don't want to us silicone.

 

WOW! No body on this site knows what to use? Don't want to use the obvious choice, silicone. Might have to take it apart some day. What ever they used originally just sealed it didn't glue it.

 

I think the gasket was glued to the evaporator case with weatherstrip adhesive . And nothing was used between gasket and firewall.

 

If that's the case then mine has been opened before. There was no gasket just some kind of black gukumpookie. It scraped off the evaporator easy but you can tell it made a good seal without glueing it, almost like blackjack roofing tar or wet patch or something. Anybody know?

 

Yup, that's the stuff. It's a sort of a body sealant, a bit more rubbery than dum dum.

I used red exterior house caulk when I added A/C to my Chevelle when I was a kid.

- Eric

 

Butyl windshield sealer aka tape or ribbon, probably 1/4", maybe 5/16". 3M & others make it. Normally in stock @ auto parts or body supply store. 3m part # 86xx.

 

WOW! A whole 49 minutes passes since you asked the first time -- before 8 AM! Take some Ritalin so we can go back to sleep.

 

Look for 3M "strip calk" 08578 - it is almost the same as the factory stuff (in the 72 Cutlass at least), less the internal string.
It is in a blue box, about 20 bucks for 60 feet. I used this and it worked perfectly. I did combine two strips together around the entire perimeter for extra sealing. Use it between the 2 case halves, too.
It is tarry but hand - pliable and never hardens. Lots of other uses for the stuff, too.

Not sure what car you are using it on, but on my 72, the blower side had a bigger gap where screws were minimal. I used twice as much there and ran the blower checking for air leaks.

 

Note the AM and PM...

 

X2...3M strip caulk is the best for this. You CAN use butyl, but if you ever need to get in there, you will be sorry you used it. Real sorry.........ever try to get a windshield out before? Imagine trying to cut your way around the whole box!

 

Thanks everybody. Yea I was kinda worried, didn't want to glue it in otherwise I would have used silicone. 49 min? BlackGold, note the day and am pm. See,I had talked my Ritalin.