All about heaters.

[jbgroby]

SB PM me your number so we can talk on the issue, way too much typing. There are several and seperate issues you will need to deal with and shortcuts you can do. I've attched a few pic for referance.

[The Rocknrod]

http://www.truckandcarshop.com/ sells heater resistors and control cable sets.

[aerotruk63]

Years ago I walked into the GMC Truck Center in Montreal with my old resistor. The original was discontinued. Another parts guy comes over sweeps mine of the counter goes to the back and comes back with one from a 73 and up truck. " Just missing the notches. " I said. "Got a file ? " he responded. Learn from the masters.

[Carfull]

Jon, Thanks for this very helpful thread.

[AngryPirate]

So, I rebuilt the stock/original heater box that came with my 1960 GMC and I replaced the heater core and blower motor.

All of the blower motor I could find that were replacements had 2 wires (+/- I assume). The stock had one post that a factory terminal slide onto.

Am I to assume that the red(+) on the new motor connects to the old orange wire that originally slid onto the terminal on the old blower motor and the black (-) just gets grounded somewhere on the truck or heater box?

First 2 pictures are of the old motor and the last one is the new one.

Random question: what is the resistor for that's in the heater box, or really, why is it in the heater box?

Thanks!

[Killer Bee]

^ pretty sure that's a ground wire, more likely for boxes not all steel..

the resistor I believe lives inside the plenum for cooling and stay out of harms way, very fragile when warm depending on selected fan speed..

my best guesses, good luck!

[AngryPirate]

Originally Posted by Killer Bee

^ pretty sure that's a ground wire, more likely for boxes not all steel..

the resistor I believe lives inside the plenum for cooling and stay out of harms way, very fragile when warm depending on selected fan speed..

my best guesses, good luck!

Thanks for the response Killer Bee.

I imagine that makes sense, since a lot have plastic boxes.

[67GMCcampercruiser]

Subscribed. Good info.

[SBPage1]

i just replaced my heater fan in my 1965 C20. Unbeknownst to me, I ordered a deluxe fan only to find it is a single speed fan. Very disappointed. Only plus is I now have heat and it is blowing semi lukewarm air. Might have to change a thermostat
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[akqj9]

I installed a new heater but the fan just blows cold air. I even duct taped around the area on the lid where the pipes go in but still just cold air

Originally Posted by akqj9

I have a 64 C10 with the thrift heater (one knob). I'm trying to take the core out to check it and I undid 4 screws that hold it in place. Each time I hear something drop like a nut or clip to thread into. I can't get the top off since there seem to be 3 screws on the back side that I can't get to without taking the entire until out. Do I need to take the glove box out to get to the bolts that hold the unit in?

[jeff_wilson70]

Originally Posted by akqj9

I installed a new heater but the fan just blows cold air. I even duct taped around the area on the lid where the pipes go in but still just cold air

Did you let the truck fully warm up 185-210 deg....and if so Do you have a thermostat installed?

[SBPage1]

Good point! My next step is to see if it has a thermostat as well. Everything else is new. I also installed a grounding strap from the heater to the firewall. No more blown fuses!

[SBPage1]

Popped off the thermostat housing today. No thermostat installed. Replaced it with a 180 degree stat and now the heater is finally blowing HOT heat!

[sstock]

I decided to tackle my heater, it had been inoperable for a decade or two according to the previous owner. Upon disassembly, I found the fan motor to be toasted and the heater core to be original and evidence of leaks. This is the thrift heater in the 1964 GMC, even though it is a full airflow heater it has a smaller core and single push pull damper and fan switch. The core measured 7-1/8", based on a poster in this thread I decided to up grade to the larger core which is a full 9.5". Oddly enough the core mounting plate is stenciled for the larger core, so it was a matter of jigsawing the metal plate. I found a full size core from the filling station, beware there are vendors that sell cores that are only 1.5" thick instead of the full 2.5", not nearly as efficient and you will have to fab up a mount for the thinner core. The core from the filling station fit like original, literally took me less than 5 minutes to fab up the mounting plate to accept the bigger core. Here are some pictures of the heater sheet metal after I glass beaded it. Some others finished. BTW, it blows hard and hot, a great modification and cost nothing more than a regular fix.
Steve

[short&wide65]

So I've read through his thread as well as lot of other heating threads and my 1965 GMC isn't like the others. It's a Canadian built truck which means a GMC body/interior on a Chevrolet trailing arm frame with a Chevrolet inline 6.

It has the recirculating heater with everything, blower motor, heater core, etc. located in cab under the dash. Controlling it all is the single knob fan control.

According to a lot of information I've read this combo shouldn't exist. The truck has been in my family since 1982 so I know it's history. After my Dad, I'm only the fourth owner. It's currently apart and in storage awaiting me to get to it. I do have pictures somewhere of the heater set up.

It was ordered as a fleet truck new by a power company so could that be why it has the recirculating heater? Thoughts?

[bigmoe]

Originally Posted by short&wide65

So I've read through his thread as well as lot of other heating threads and my 1965 GMC isn't like the others. It's a Canadian built truck which means a GMC body/interior on a Chevrolet trailing arm frame with a Chevrolet inline 6.

It has the recirculating heater with everything, blower motor, heater core, etc. located in cab under the dash. Controlling it all is the single knob fan control.

According to a lot of information I've read this combo shouldn't exist. The truck has been in my family since 1982 so I know it's history. After my Dad, I'm only the fourth owner. It's currently apart and in storage awaiting me to get to it. I do have pictures somewhere of the heater set up.

It was ordered as a fleet truck new by a power company so could that be why it has the recirculating heater? Thoughts?

I got one of those basic recirculating heaters (and the two delete plates) from a 65 farm truck and put it in my 65 Gmc. I wanted to get that ugly deluxe heater out of the engine bay.

[short&wide65]

Originally Posted by bigmoe

I got one of those basic recirculating heaters (and the two delete plates) from a 65 farm truck and put it in my 65 Gmc. I wanted to get that ugly deluxe heater out of the engine bay.

Interesting. I see you're in Manitoba, maybe the recirculating heater was standard through 1966 on Canadian trucks? I'm guessing your truck and the farm truck were Canadian trucks?

I don't want any of the heater in the engine bay either but am looking at a Vintage Air/Old Air unit for mine.

[bigmoe]

Most pickups I’ve seen around here had the deluxe heater. When I said farm truck I meant a a bigger grain truck. Maybe those weren’t used much in the winter, more at harvest time.

[short&wide65]

The Thrift and the Deluxe heaters were definitely options in Canada. They are mentioned in the the Canadian service manual I have. The recirculating heater is as well but only in the 1963 manual, not the 1965 supplement.

[G8rN@te61]

So is it my understanding from reading this thread that in my 61 with deluxe heater the wire going INTO the box in engine compartment is to a control valve mounted on the heater core. This heater core with valve is not sold by any vender. So basically without it my heater is on full blast but sounds like this is even barely enough in very cold temps. Here in NC Im probably fine since I don't take it out if its snowing which it rarely does here in Charlotte. Looks like there is a vender who can mount it but its hundred of clams which id rather spend on other things.
-Nate

[Captainfab]

If you're talking about the cable that goes into the heater box, then yes that controls the ranco valve which controls the heat output of the heater. If you need a new heater core, you will have to purchase the correct size core for the '64-'66 Deluxe heater and have the tank on that side switched. If the ranco valve is not working or leaking, it can be bypassed or repaired.

[G8rN@te61]

Ok. I have a '61 and theres a non-correct heater core in there now that I wanted to change out to the correct one which I did purchase from car and truck shop but it doesn't have the valve on it. Looks to be pretty expensive to get it put on so Ill just not use it.

[Captainfab]

As far as I know no one makes or sells the correct heater core for a '60-'63 Deluxe heater.

[4thgencreamsicle]

So I got the cage from Brothers and the blower motor from LMC. If I put this together the way it’s SUPPOSED to go, with this little square dude on the shaft first, then the cage, the cage blades rub the box all the way around when installed...bad. But if I remove this, it would fit perfect, I’d just need some washers to take up space on the shaft. How important it that square spacer? Seems like it would keep the plastic from getting worn at the base.

Or do you trim the cage blades? If so, with what? (Leaning towards this one, but not sure an exact o knife is the smartest choice since it’s kinda hard plastic, I’m kinda clumsy, and fingers are important)

Or do I buy a new cage from LMC and they magically match up because they were supposed to be bought together all along?

Help a girl out.

[Asshat]

Not sure if it was answered here, but the motor for the heater has only one post for electrical connection. I presume this is (+) and the motor is grounded through the frame? Or is there a separate ground wire?