Heater core replacement

[jwright]

New to me, nice 1978 Scottsdale k20 4x4, heater core was leaking, got the new one in but the old insulation material is trashed from the year, rodents and antifreeze, was thinking of using dynamite to insulate before going back with heater housing, would this be an issue with fitment? Old stuff so thick dynamite obviously isn't, any comments or advice. If I didn't have to disassemble the dash I would replace with original firewall insulation, don't wanna go that deep.

 

[ali_c20]

Welcome. I think you're good with dynamite.

 

[Grit dog]

lol….
Not totally understanding. Are you asking about the firewall and floor insulation? If so, dynamat or similar would work just fine. IMO.
Trying to think just did heater core in the 86 last year. It doesn’t go behind the heater box IE between the flanges on the heater box and the firewall as far as I remember so thickness should not be an issue?
Or are you talking the insulation gaskets on the heater box components themselves? For that I used sticky foam tape.

 

[Fat 454]

we just replaced one in an OBD. Used some strips cut from an old craftsman draw liner ( thin heigh density foam sheet ). Worked a treat.