What to use on heater box for sealing??

[HAFROD]

On my ac/heat box on the firewall, I noticed it had some kind of sealant that never dried hard on the top lid. What is this goopy stuff and where do I get it? Also, I bought a new heat/ac box seal for the firewall from OPG. Do I need to use a sealer on it with the new gasket or install dry?

 

[bbarbulo]

Acousti-seal from LePage is very similar to what you describe. Its like a thick tar in a caulking gun. Its messy but nicer than roofing sealant products.

 

[FE3X CLONE]

It's 3M strip caulk. Pricey but is just like original.

But it wants to stick to anything so it helps to wet your fingers to help smooth it out and keep it from sticking to yourself.

http://3mcollision.com/3m-strip-calk-08 ... Caulk.html

 

[Fox80]

When I did mine I was going to paint it and the inside of the car and the underside all at the same time as well as the frame (I did not like the gloss black I had originally painted it) the butyl that is mentioned is ok to use and is close to what the factory used but in my opinion a quality urethane sealant is the best choice for this. Sealant as come a long way in 35 years since my car was built we should try to use what we have

 

[Blake442]

3M strip calk, just like FE3X showed.

Urethane is nice on parts you don't need to take apart...
It's just a heater box, not a boat! :lol:

 

[tc1959]

3-M Strip Calk is what the factory used. I bought a box off E-Bay when I redid my heater/AC box.

 

[Longroof79]

Another proponent of 3M strip-caulk...