replacing heater core on '69 with a/c

[SAC69]

I'm about to replace the heater core on my '69 with a/c and have heard horror stories about the effort needed. Does the entire dash really need to come out, upper & lower? Any shortcut info or other tips would really be appreciated.

Thanks

 

[JeffTepper]

Tom:

If the evaporator case is like the one in '67-'68, it has to come out of the car to get to the heater core. On those two model years, the evaporator case separates from the fan housing and defroster housing before it comes out from the underside of the dash (after you remove the glove box and center console if so equipped). Not sure if the '69-'70 dash has enough room for the evap box to come out that way as the lower dash below the glove box seems closer to the firewall than on a '67-'68. In any case, poke around there and see what kind of room you have before you chart a path. Note, you do need to disconnect everything from the evap box including the a/c lines so that means you need to evacuate the system of freon. Note further that R12 is still readily available and from what I can gather, it is a better refrigerant for these old rigs. Lastly, once you are inside the evap box, you may as well completely rebuild it meaning fresh foam, flushing out the evaporator core, pressure test it, and replace the expansion valve, the receiver/dryer, vacuum lines, and check the function of the various vacuum motors (there are 4 of them IIRC) and anything else that looks worn out. Good luck!

 

[miketyler]

AC plenum box was first on the list of things I had to do on my 70. The car already had upper dash removed. I ultimately had to remove the lower dash as well but maybe could have gotten by with only taking loose at passenger side and middle. Agree also on the full plenum rebuild. Parts are cheap and there's no telling what all has accumulated inside that thing....

 

[cmayna]

And us without AC just sit back and sip on our sodas.......