heater core removal and replacement

[john nicholls]

I have one out of a 78 Royale for $50. Are you coming to Tallahassee?
--
John Nicholls,
78 Royale w/455
Pensacola, FL

 

[charles boyd]

It does come out the front and any competent radiator repair facility should be able to clean and repair it.

> No, we are not. Thanks for the offer.
>
> It hasn't failed but got a lot of green staining around it and while redoing all the ac/heater motor and switches, thought I might change it out.
> I saw in the parts list that Four Seasons # 94530 is suppose to work, but I don't know if it a drop in as I don't know the dimensions of the
> original or the suggested replacement. The inlet and outlets don't have the fancy turns in them like the original but they are bent in the same
> direction.
> Just wondering if it is the same core dimension as the original or if that matters at all.
> Then there is the problem of getting it out, does it come out from the outside or do you have to tear the dash apart to get it removed?

--
C. Boyd
76 Crestmont
East Tennessee

 

[tyhardiman]

The heater core comes out from the front. There were three versions of the dash HVAC system but they all have the same procedure for your goal.

Here are pics of the heat & a/c box. It is under the "hood", actually dead center between the two hoods. You will need to remove heater hoses,
windshield washer reservoir, anything else in the way to get to the cover of the box. The cover that you are removing can be identified by the
"Harrison" sticker on it.
http://www.gmcmhphotos.com/photos/plenum/p14766.html
http://www.gmcmhphotos.com/photos/hvac-original-and-mods/p63542-1977-2f78-ac-box.html

A pic of the Harrison unit with the cover off, allowing access to the heater core:
http://www.gmcmhphotos.com/photos/plenum/p14771.html

A pic of the heater core:
http://www.gmcmhphotos.com/photos/dash-air-conditioning-redesign/p30759-slide10.html

Another link with good pics:
http://www.gmcmhphotos.com/photos/plenum/p14766.html

Ken Henderson's rebuild:
http://www.gmcmhphotos.com/photos/dash-air-conditioning-redesign/p30752-dash-air-conditioner-redesign.html

Ken was modifying the problematic 1975/1976 dash HVAC by drilling holes in the firewall. Your 1978 does not have this problem, simplifying your
project.
--
Ty Hardiman, Norman, OK / Member FMCA-GMCMI-GMC Classics / August 1977 Kingsley TZE167V102390 / 26' / 403 / 3.55 / 16" Wheels / Quadrajet / HEI /
Previous Owners: Basil LeBlanc, Dan Ramker / Original Owner: William Strahm, Loveland, CO

 

[Bob Dunahugh]

It comes directly out the front. It's too much of a pain to replace twice. YES. Any radiator repair place can fix it. But where is it going to leak next year. It has to have the bent in/out tubes identical to the original. I got a new replacement from Jim K at Applied before it ever leaked. I change my coolent every two years. I will never have to replace it again. Bob Dunahugh 78 Royale