Heater Core on A/C Truck Questions
 

Removed my 50 yr old heater core and had it recored. When I removed the core from its 50 year place a bunch of goop, friend said was called Dum Dum and stuff on yellow rag, started falling out from various places where the core was. So I managed to get it back together today without the goop and am wondering if it is really needed ? The core is just slightly touchng the case in one spot, pictured, and wondering if this could pose a problem with case melting from the core heat. Also I removed the 2 relays from the corebox and wondering if should just reuse or replace. I took them off and detailed them and put em back on.

Re: Heater Core on A/C Truck Questions
 

Strip caulk, or butyl caulk. I believe they did it to insulate it from vibration and try and keep airflow going through the core and not around it; but they needed a material that was resistant to moisture(condensation) and wouldn't dry up.

Butyl caulk. :)


If the relays work but you have money burning a hole in your pocket--or you absolutely hate doing work on your truck--then I guess you can replace them just for the heck of it. But otherwise use them till they break, I guess. Your call.


EDIT: Caulk: https://www.amazon.com/3M-08578-Blac...a-496944296532


I have this and other versions of it and let me be clear: While I don't think it's useless, it's a gawddam mess and I have found it a little tricky and gooey to work with. Have fun.