heater core R&R

[Kurt Combs]

I am being lazy and not wanting to lay on my back to figure this out, how difficult is it to R&R the heater core on a 1972 F-250? It currently has dealer installed AC, but I am permanently removing that from the cab when I do the heater repair. Any help appreciated. I did this on a 1981 Toyota Cressida years ago and I swore I would never do another one. You had to take out the front seats and disassemble the dash cluster and then work your way right to the core. I have never before, or sense, felt I had something apart that I might not be able to reassemble. My assumption is that the truck will be much easier. Right???

[fordman]

once the dealer a/c is out ofthe way just take the heat box out of the truck and takeit apart. you will see the core when it comes apart. remove it and replace it. then put it all back together. this is a ford not a toyots or datsun. i hated doing the one on that datsun. you had to remove the entire center console to fix it. i never did it. i just bypassed it. and froze all winter long.

[Banjo]

How do you know you need to change your heater core? Is it leaking or just not heating? If you're not getting heat, are you sure the inline heater valve isn't corroded/frozen closed?
If it's not physically leaking into the cab floor, it could be just plugged and might could be blown out w/hose or air compressor and hose combo, leaving intact (from firewall side). If you're just noticing leak, it could be leak from elsewhere (wiper transmission seals into cowl).
OR, are you getting the dreaded misty fog onto your windshield accompanied with weirdo smell, that's the quickest way to know it's the heater core.
Reason I'm saying be sure, I thought for sure my heater core was leaking until I got in my truck at night during a hellacious rain storm and found my wiper transmissions were leaking (badly) at the cowl and one side was running right down under heater core box, I would have bet money on heater core, but wasn't.

[Banjo]

oh yeah, meant to add, during this mentioned rainstorm, I was upside down in cab for quite awhile w/strong flashlight gently moving this and that until I was positive I'd found my leaks. What I was positive was windshield gasket and heater core turned out to be only windsheild wiper transmissions, which pass right through cowl. Once loosened and squirted w/neoprene chimney caulk, not a smidgeon of water penetrates now, dry as a bone.

[Kurt Combs]

Banjo,

My control cables, defrost tubes and control valve were all in need of repair or replacement and I thought the previous owner said it leaked. I purchased a good dashboard control unit with the cables on Ebay and the core is not expensive, so I thought I would just fix it all. I have it all back together now and it wasn't too bad, but it did take a few more hours than I expected. The core was corroded, so it was good that I changed it. Thanks for the suggestions.

Kurt

[Banjo]

I'm glad you are not freezing to death in your Ford now!

[kaptnkaos]

Once loosened and squirted w/neoprene chimney caulk, not a smidgeon of water penetrates now, dry as a bone.

I've never seen this before.
Where would you get some of this stuff ???

KaptnKA S

[fordman]

he might be talking about wet and dry roof tar in a caulking tube.

[basketcase0302]

Banjo,

turned out to be only windsheild wiper transmissions, which pass right through cowl. Once loosened and squirted w/neoprene chimney caulk, not a smidgeon of water penetrates now, dry as a bone.

Thank you man!

I've had a leak in my 71' Ranchero in that area that I've tried numerous times to track down and never thought of that.

Now if I can just get upside down under the dash in the "Chero".

Basketcase

[Banjo]

If you'll go to the roofing area of local Lowe's or whatever, they make a caulk tube of black chimney/fireplace caulk that'll stop a leak in a creek! Goes on good, smooths out good by fingers after and seals like nobody business! Old banjo would not lie!
You cannot find the wiper transmission leaks until it's pouring big time and night and you suspend yourself upside down UNDER dash with most of your stuff removed to find. I was so dedicated to stop my leaks, I removed ENTIRE heater assy, aftermarket cassette player, heater control panel and ashtray assy. Now, this didn't bother me because I needed to replace all my old heater/defrost cables anyway and wanted to get remnants of old dash pad out and plug holes with metal caps and paint my inner floorpan with bedliner to help insulate (which I did). It was VERY hard to find these wiper transmission leaks and even when I did, VERY hard to remove linkages to get them out to squirt the black neoprene chimney sealer stuff under them (forming a gasket). Good luck, Banjo.

[theogre5150]

Ok......I am now having some of the same problems. When I get in and turn on the heat, I get a funky antifreeze smell, the misty fog, and last night I noticed the drips inside of the cab. What do I need to do to fix this?

[fordman]

probably put in a new core. it sounds like its leaking.

[theogre5150]

What do I need to do to replace it? Where is it located?

[fordman]

it is under the dash on the passenger side inside of the case.
you will have to drain the antifreeze.
remove the heater hose from outside the firewall.
remove the three nuts on the firewall that hold the case in.
take the case apart and remove the core.
put the new core in and everything else back together and it will be good as new. don forget to remember which side the heater control valve on the heater hose went on.

[sargentrs]

Hey, speaking of which....what hose from the water pump goes to which port on the heater core (in the engine compartment). The PO put a shut off valve on one of the hoses, port closest to the pass. side. Heat blows constantly winter or summer. When I shut the valve off, antifreeze leaks from behind the heater box. I've just been living with it. By the way, it's a 302, bare bones truck.