Heater
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New User
Joined: Oct 2014
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Heater
Just bought my 79, 3 on the tree. I'm in the Deep South so it doesn't get SUPER cold. I ran the heat a couple nights ago and it didn't even get warm. The truck is all original. The fan blows on all the settings. I checked yesterday and I'm almost all out of coolant, after it was full last week. I've done some research on here and I think it's probably the heater core? (Easy to change out?) I'd like to know for sure before I get too deep into it. I don't have a lot of mechanical experience. This has been a 'learn as I go' sort of truck and I've enjoyed it throughly. Any help is appreciated.
I almost forgot. I don't have ac, just heat.
I almost forgot. I don't have ac, just heat.
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 82
From: NorCal
In addition to checking the thermostat, flush the heater core by disconnecting the hoses in the engine compartment and flushing it out with a garden hose.
Also check that the heater valve is actually opening and allowing engine coolant to circulate.
Also check that the heater valve is actually opening and allowing engine coolant to circulate.
Senior User
Joined: Apr 2012
Posts: 324
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From: Spencer Mountain, NC
Be careful when flushing a heater core with a garden hose. If you apply pressure over about 15 psi you could blow out the core. Many city water supplies run over 60 psi.
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Postmaster
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It wouldn't hurt to make sure the heater hoses are hooked up. Generally 2 5/8" ID hoses that run to the pass side firewall. If the heater core was leaking the PO may have removed or blocked the hoses. Also check to see if a valve was added to one of the hoses (non original).
Another check is movement of the heater door. Have a helper slide the temp control back and forth. If you peek under the dash, around the middle, you should be able to see the cable moving a lever on the heater box.
Another check is movement of the heater door. Have a helper slide the temp control back and forth. If you peek under the dash, around the middle, you should be able to see the cable moving a lever on the heater box.
Fleet Owner
Joined: Dec 2009
Posts: 20,678
Likes: 82
From: NorCal
So do you know if it does? Didn't think so.... it's not like the OP is providing detailed info.
Moving on......
Mountain Pass
Joined: Nov 2013
Posts: 243
Likes: 10
Just replaced my blower motor. Took about 3.5 hours. Would be about the same for the heater core. There are 3 bolts in the engine bay to take off . 2 at the blower motor and one right behind the engine. Disconnect the two wires from the blower motor.
Move to the passenger floor. Remove the cable that controls the heat/defrost. I didn't remove the temp cable. Remove 4 or 5 screws that hold the vent. Remove the electrical connection to resistor. Then twist tug pull the heater box until it comes out. from there you should see how to remove the core.
To put the heater box back in I found it helpful to push it up using the heat core tubes with your hand up against the firewall. Once I got it kinda close my son helped me pull the motor wires thru and to align the holes.
I also used a water hose to clean out the core and blew some air thru it to remove some water.
Move to the passenger floor. Remove the cable that controls the heat/defrost. I didn't remove the temp cable. Remove 4 or 5 screws that hold the vent. Remove the electrical connection to resistor. Then twist tug pull the heater box until it comes out. from there you should see how to remove the core.
To put the heater box back in I found it helpful to push it up using the heat core tubes with your hand up against the firewall. Once I got it kinda close my son helped me pull the motor wires thru and to align the holes.
I also used a water hose to clean out the core and blew some air thru it to remove some water.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
No factory A/C, no Hi/Lo comfort vent system: No heater valve.
Tuned
Joined: Oct 2006
Posts: 361
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From: Eagle River, Alaska
Might check the Heater hoses for temp. A blocked core will at times show as one hose reaching engine temp and the other staying cooler. With good flow and no valve in one of the lines, you should notice both reach engine temp as it rizes.