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Please help! how to R n R heater system ?

Hello,

how do I go about removing for repair the cab heater and windshield defrost system in my 62 IH truck?

The dash and heater controls are the style seen in the second half of this video:
'62 International Harvester and the automobile driving museum: hcctv - youtube

But my actual truck and situation is seen in this second link, where the hose goes through the fender and disappears into a space the fuel line comes from, and must go through some hidden hole in the side of the cab.

http://forums.IHPartsAmerica.com/at...-many-questions-so-overwhelming-firewall1.jpg

The heater controls are all frozen solid, and not sure how they're supposed to work. I bought a large 2-volume photocopy of the IH service manual for my truck, but not one word is mentioned about the heat/defrost system.

Can anyone please help? How do I remove the cab heater system to install the proper heater core that has hose connections for through the firewall, etc? And was there any service supplement ever printed that covers this heater system?

Thank you.
Steve
 
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Hi,

removing the heater box was actually fairly easy. If anyone ever asks, just remove the nuts from the three studs sticking through the firewall, remove or cut the 2 heater hoses and the thing can be pulled right out. Guess I'm just losing my confidence in my old age ;)

however, the main problem still remains. I've never seen an IH heater system before so not sure what parts should be in this heater box. I'm fairly certain the water valve is wrong as its clamped to the box bottom with a hose clamp. And what is that copper colored coil for? - possibly a heat-sensing coil but its not hooked to anything. Can anyone give me any insight as to if I have the correct heater core and/or water valve in this thing?
Picture of the front and the back insides are in the two links below.

Thank you for any help you can provide.

Steve
 

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FDChappie

Active member
That "copper coil" looks like it might be a bi-metal spring to function as a thermostat for the heater.
 

MarkO

Member
The water valve looks about right.

Be glad you don't have the high capacity heater--the valve is mounted inside the box surrounded by the 'u'-shaped heater core. It is not easy to get to at any time.

When I had to replace the valve I purchased a universal valve and put it inline on the firewall side--I had plenty of cable from the dash. Now if I ever have a problem with the valve it will leak all over the engine compartment and not all over the floor or my wife's feet.

Not sure what the coil's purpose is.

While you have everything apart, now would be a good time to lube up the fan motor.
 
you might get a better response here:oldihc
That could be true, thanks, I think I'll try it.

that "copper coil" looks like it might be a bi-metal spring to function as a thermostat for the heater.
That's what it looks like to me too as I can see on the other side where it was disconnected. But I don't see much practical use for it. If I want less heat, I'll just open the valve less, and if I want more heat in the cab, I don't want any bi-metal coil holding it partially closed just because the box is already hot enough.

the water valve looks about right.

Be glad you don't have the high capacity heater--the valve is mounted inside the box surrounded by the 'u'-shaped heater core. It is not easy to get to at any time.

When I had to replace the valve I purchased a universal valve and put it inline on the firewall side--I had plenty of cable from the dash. Now if I ever have a problem with the valve it will leak all over the engine compartment and not all over the floor or my wife's feet.

Not sure what the coil's purpose is.

While you have everything apart, now would be a good time to lube up the fan motor.
I'm not so sure that's the correct valve for this box. If you notice it has to be held in place with a hose clamp. And, what you can't tell from my pictures, is that its output is no where near the correct location. A second hole was drilled in the back of the box for the bottom hose, which then had to go through another hole in the fender rather than the firewall.

Good to know about the high-capacity heater. I've never seen one but was wondering if I should look for one. Your experience answered that question.
Actually there is so much wasted space in this box that it would not take much to redesign it to add another heater core on a shelf under the stock one. I'm thinking a little about that too. Or perhaps three heater cores if they were on edge rather than laying flat. That should be enough to heat the entire crew cab on the coldest of nights. As long as I pay careful attention to partitions and maintaining the way the air is directed, is there any reason why 3 cores in series would not work? On edge might be better because when I opened the back of the box, on top of the core the box was completely filled with dirt, leaves, dead grass hoppers and other long extinct bugs blocking any possible air flow across the core. (I think I like to redesign things in addition to just fixing them.)
I checked here and a couple other places and this heater core and valve is no longer available. But there must be a hundred other configurations of cores available.
Is there any possible orientation a heater core won't work in? Or water flow direction? And what about a couple cores in series - sound like that would work?

And I'm glad you mentioned the fan motor. Not sure if I would have thought about it. You're right, now is the time to service it.

And I never thought about putting the valve outside in the engine compartment. I'll have to give that some serious thought too. But I definitely like your "outside the box" thinking. ;)

steve
 
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FDChappie

Active member
If you're going to do 3 cores plumb them in parallel, not series. Most of the heat will be pulled out of the water after it's gone through the first core.
 

Cudamank

Member
I just picked up a silmilar heater, same box and core, but it did not have the heater control valve inside. So not sure if that is an addition or what. Did you get yours figured out?
 
I just picked up a silmilar heater, same box and core, but it did not have the heater control valve inside. So not sure if that is an addition or what. Did you get yours figured out?
Hi,
yes I did. Your box probably didn't have one because it started to leak, or rusted and corroded to the point where it did not work. So the previous owner just removed it completely. And a nos IH replacement valve that goes inside the heater box is very expensive, if you could find one. And its still way over-engineered and unreliable for what it does. To me, all it should do is turn the flow of hot water into the heater core either on or off, or somewhere in between depending on how much you push or pull the cable.

I found two different replacements that works better than the stock IH valve ever did, imho. I intended to do a write-up in my build thread, but not sure where I put my notes now. So I don't remember the part number or manufacturer of one of them.

The other is a heater control valve from a mack truck. Mack part number: 7979-173084 f-model 1975-1981.
This has the proper sized heater hose connections with the proper orientation to each other and to the control cable. And the cable opens or closes the valve in the correct direction to work with the IH 60's pick-up truck's dash heater control lever. With shipping they're presently selling for $20 on ebay.

The one on the left is the actual proper stock, in-box IH hot water heater control valve. And the other is the mack water control valve. So much simpler and it works as smooth as butter. It needs the two fittings as shown, and some type of strap to hold it in place on the floor of the box on the inside of the heater box. Then you have a heater control valve that works inside the heater box and connects to the water hoses and control cable like IH originally designed.

On the first picture, see those two rubber grommets? A cable goes through one to the water control valve. And a cable goes through the other one, then loops under and behind the heater core to a air directing flap. Hope this helps.

Let me know.

Steve


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