Hey guys, my son was recently given a 1986 Chevy 1/2 ton.
The heater core has been unplugged. Its my guess that the heater core was leaking and the previous owner simply didnt want to bother fixing it so, it was simply by-passed.
I have since purchased a new heater core and new heater hoses.
However, I have never had to replace a GM heater core on a P/U with A/C.

So, my question to y'all would be, how does one get to the a heater core on a 1986 Chevy P/U with A/C?

Thanks.
Rich.

 

It has been a while but I believe it is all very easy to access from under the dash. IIRC you need to take out the glove box to get to a few of the upper screws. May need to remove the right side kick panel as well but probably not.

 

no need on the kick panel, heater unit comes out from under the dash, three nuts on the outside of the firewall, if I remember right. Been a while since I've done one, but I have done lots.

They don't take that long once you get into them, not like the dodge nightmare design.

 

Not much help, but I had a 95 that I did a heater core on, and all I did was pull some trim out of the way, and I think that cover to the blower. It slid right out. Very easy.

 

Removed the glove box already.
What I see:
1) Inside the cab: All but one screw faces the engine compartment (Total of four that I can see).
Removed the one (and only screw) that can be removed from inside the cab.

2) Inside engine compartment: On the A/C cover, two screws visible coming through the firewall with 10mm nuts. Removed these two nuts (one is only accessible from under the truck - fun ).

Result: Blower/vent box inside the cab is still firmly in place - no sign of even wanting to move.
Also, the two nuts that were removed dont appear to be aligned with the three remaining screws visible inside the cab.

Hence my reason for posting.
I have several GM shop manuals and none address the removal of the heater core.

 

I remember doing one chevy truck that I believe was a mid 80's and had to partially remove the RT FRT plastic wheel well liner to get to one last bolt from the engine side.

I wish I had access to one to look at. I'm sure the memory would kick in! Can you get any pictures of the areas you are looking at? That might help as well.

 

there are three that face into the engine bay. You need to find the third one.

 

Also-some have a gasket from heater box to firewall and it is stubborn to remove

 

Yeah, I was able to access all the bolts from either the engine compartment or from under the truck.
While not fun, all the bolts are accessible one of those two paths.




Yes, the first two are easy to access. The the third? Well.... it appears that the third may come out inside the A/C box. From what it appears, the A/C box needs to be removed in order to access the nut on the third bolt.
I attempted this last night and was not successful.

 

After taking a better look (now that its daylight), I was able to find the third nut, just where RockCrawler said... under the A/C box and just above the passenger fender well.
I will try to access this via a swivel, but may end up having to loosen the that fender well.

ugh.

 

That should be all there is. Let us know how it turns out.

 

Done.

Had to use a swivel and all my extensions to get to that third nut hidden under the A/C housing and on top of the inner fender well, but I got it.
Then fought to actually get the heater core out of the heater core housing, but that too finally gave and all is now back together.
In the process, discovered the truck has no thermostat.
So, a bit difficult to get her warmed up... but on a short drive, the heat started to work.

Thanks guys, appreciate all your input.

Rich

 

I would of gladly traded your heater core swap for mine in my 2000 sunfire, 14hrs later I had heat, just in time for winter.

 

Yeah, Ive heard of many horror stories about various heater core installs.
I understand that our trucks are among some of the worst to have to change.
Not looking forward to that day.
14 hours... I havent had 14 hours of contiguous free time since the birth of our first son!
LOL, something that takes a planned 14 hours would take me two months!

 

Last one I did was in an '88 dodge gasser. It was 35* and raining and the second week in October. Took nearly 8 hours but I had heat in the end.....

Glad yours went well.