heater core replacement ??

[m00n1957]

heard it was a major PITA, anyone ever replaced theirs ? anyone got any tips on where to start ? mines a 86 with a/c. just got finished with restore last summer now i can tear it back down for this, just my luck.

[JFetter]

Nice looking truck!

I just had my core all apart and washed it clean, etc... but I have a 78 w/o AC. (which may be quite different?)

The duct work assembly pulled out from under the dash after removing 3 nuts on the opposite side firewall. After that it's pretty straight forward.

[bigd65]

Read this thread, ALOT of info in there

http://67-72chevytrucks.com/vboard/s...d.php?t=460942
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[bohmankid]

You can do the whole thing laying on your passenger floor.. Take out your glove box, then all the air ducts in front of the core, unclamp the hoses under your hood and pry it out. It is a PITA. I did mine about 3 years ago and don't remember details.. Good luck!
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[Ski-me]

Originally Posted by bigd65

Read this thread, ALOT of info in there

http://67-72chevytrucks.com/vboard/s...d.php?t=460942
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That's a good write-up. I did my 89 a few years ago and the hardest part was getting the core out of the plastic box. Take your time and gently pull it appart. To access one of the lower nuts inside the engine compartment, I actually loosened up the inner fenderwell and pulled it down some. This allowed me to gain some access for that bottom two nuts.

[piecesparts]

I have changed a few of these. The trick is to take the glove box completely out of the dash and then use a set of sockets with a long extension to get to the nuts on the outside of the cab. Be sure to take the heater hoses off of the core before goign too far. There is a nut on the inside of the cab, that is tied to the two heater core covers and it is the one that will give tou some grief, if you do not find it. DIsconnect the heater control by taking the screw out of the adjustment slide and lift the cable off of the swing arm. Disconnect the vacuum hoses to the damper controls on both ends of the heater housing and then the whole rig can come out and be taken to a work bench. There are four screws that hold the heater core into the housing and then when the housing is loose, there are screws on the metal restraining pieces for the heater core. When you take the housing apart, you can pull the air damper control arm out of the damper, by pulling upward and out, this allows for the housing to be seprated easily. Remember the damper position when you take it apart, so that you do not go into a frenzy trying to go back together. There is no reason to do anything with the outside housing , just get the inside loose and pull it off of the firewall.

There is very little reason to lay down under the dash on this job and you can do everything with the seat in the truck.

[Hevy]

Replaced mine yesterday. It's not that hard but take your time.
I pulled my bezel, dash pad, glove box, all air ducts, and then the box itself. Pulling everything out gives you more room to work and I wanted to clean everything before re-installing.
Before anything else remove heater hoses under hood.
There was one bolt inside the cab on the right side of the box and the three nuts on the outside studs. If you have the extensions and swivel you can remove all the nuts as is without removing fenders, etc...
Even after everything was removed the box was stuck tight to the firewall after 36 years so you might have to pry it off, don't break anything. One vacuum hose on the left and one in the middle (mine cracked and broke off), remove the temp. cable and remove the case from truck. While the box is out you may want to check the vacuum diaphrams to make sure they both work before you install everything again. To split the box (on my '77 with A/C) there were eight screws, three by the temp. door arm and five holding the halves together.
Split the case and there is the heater core. Four screws and metal brackets hold it in the case, remove those and swap it out.
Reverse everything and add coolant.
I'm sure I forgot something but that's it in a nutshell.