What is used to seal heater hoses to heater box on 1968 Chevy C10
 

I am replacing the heater hoses on my 1968 Chevy C10 shortbed 396 fleetside that did not come with air conditioning.

What is the sealant that they used to seal the heater hoses to the heater box in order to seal off the opening around the heater hose?

Could some regular caulking be used?? Maybe some of that old style automotive front windshield rope sealing be used???

Re: What is used to seal heater hoses to heater box on 1968 Chevy C10
 

I’d use pipe wrap insulating foam and maybe a little of the black sealer (dum dum, monkey $hit, windshield butyl) to keep it in place.
There’s probably a specific seal for that, like the AC evaporator case seals.

Re: What is used to seal heater hoses to heater box on 1968 Chevy C10
 

Most residential HVAC places sell the packing. I used it to seal my lines in the plenum on my central air. Very dense black rubbery roll . Single side adhesive .

Re: What is used to seal heater hoses to heater box on 1968 Chevy C10
 

Well I'm about to find out. After putting a coolant overflow tank on my truck, and finding what I thought to be every weak spot on the ride, now my heater core is leaking. I'm about to have an all new collant system. Live and learn I guess.

Re: What is used to seal heater hoses to heater box on 1968 Chevy C10
 

Yeah I am going to replace my heater core in the near future also even though it is not leaking but it has most likely never been replaced.

Re: What is used to seal heater hoses to heater box on 1968 Chevy C10
 

I just replace my heater core last year, and I used black caulk, just to fill in the gaps. It gives it a cleaner look and it’ll be easy to remove if the need arises again

Re: What is used to seal heater hoses to heater box on 1968 Chevy C10
 

I replaced mine a couple years ago and didn't use anything. Hasn't caused any problems yet.
just on a side note I used plumbers putty to seal the heater box to the firewall and it worked great.