heater blows cool
Senior User
Joined: Mar 2004
Posts: 103
Likes: 0
From: Cincinnati
don_79f250,
Thanks for the info. I plan to start working on mine tonight. I too have seen the signs many times and have replaced my share of these. I saw the trickle of antifreeze on the rubber mats, but just didn’t have the time to dive in. Taking out the entire heater box to change a heater core was something I just wasn’t looking forward to. Well at least I don’t have to remove the front passenger side fender like I hade to on my son’s Camero.
After a week of wiping down the inside of the windshield, I find I can wait no longer. When I turn on my heater, my cab fills up with smoke like a Cheech and Chong movie. No kidding, you can’t even see the road it is so bad. That or I am finally experiencing those Jimi Hendrix flashbacks they warned us of years ago!
Again, thanks for all the help.
John24255
Thanks for the info. I plan to start working on mine tonight. I too have seen the signs many times and have replaced my share of these. I saw the trickle of antifreeze on the rubber mats, but just didn’t have the time to dive in. Taking out the entire heater box to change a heater core was something I just wasn’t looking forward to. Well at least I don’t have to remove the front passenger side fender like I hade to on my son’s Camero.
After a week of wiping down the inside of the windshield, I find I can wait no longer. When I turn on my heater, my cab fills up with smoke like a Cheech and Chong movie. No kidding, you can’t even see the road it is so bad. That or I am finally experiencing those Jimi Hendrix flashbacks they warned us of years ago!
Again, thanks for all the help.
John24255
Postmaster
Joined: Feb 2003
Posts: 4,043
Likes: 4
Originally Posted by John24255
73F350SC,
[snip}
Actually, the air conditioned models appear easier, it looks like these can be replaced through the engine compartment.
I will write back and let you know how long it takes.
John24255
[snip}
Actually, the air conditioned models appear easier, it looks like these can be replaced through the engine compartment.
I will write back and let you know how long it takes.
John24255
You know, looks are soooooooo deceiving. Don't try to access the heater core from the engine compartment in factory A/C equipped trucks.
Posting Guru
Joined: Sep 2003
Posts: 1,192
Likes: 1
From: lino lakes, mn
bh2112 you say it looks like an AC heater box check and you have two hot or should I sat equally hot heater hoses there is a "vacum motor" under the dash on top of the heater duct check to see if that is working by changing lever positions while watching there is also a temp valve inline on the heater hose check that to see if the vacum is able to pull it all the way open sometime they will gum up and require a little assistance to move a pliers will work most times the chilton manual for ford trucks has a fairly good discription on the AC heating system for these trucks
Senior User
Joined: Mar 2004
Posts: 103
Likes: 0
From: Cincinnati
bh2112,
Since the heater core on my 79 F150 4X4 no-air, developed a leak, I replaced it yeaterday. To do so, I had to remove the entire heater. Good thing I did, it was full of soggy leaves. As was stated earlier, to remove the heater, there were 3 nuts on the outside, one near the center of the engine, 2 near the blower motor. Also, be sure you disconnect the blower motor wires, the blower comes out with the heater. There were 5 screws on the vent door that have to be removed, to get to these the clove box lining has to be removed. One last item to remove is a heat vent which is held on by two clips.
On my system, there is a flap between the heater core and the outside vent. This flap is controlled by a cable from the heater control temp selector. As the selector is moved from cold to hot, outside air is blocked allowing only heated air to enter the cab. If your flap isn't working properly, your heat could be mixing with a lot of cold outside air, making the heat output warm at best.
If your system is like mine, you should be able to see the flap once you remove the vent screws.
John24255
Since the heater core on my 79 F150 4X4 no-air, developed a leak, I replaced it yeaterday. To do so, I had to remove the entire heater. Good thing I did, it was full of soggy leaves. As was stated earlier, to remove the heater, there were 3 nuts on the outside, one near the center of the engine, 2 near the blower motor. Also, be sure you disconnect the blower motor wires, the blower comes out with the heater. There were 5 screws on the vent door that have to be removed, to get to these the clove box lining has to be removed. One last item to remove is a heat vent which is held on by two clips.
On my system, there is a flap between the heater core and the outside vent. This flap is controlled by a cable from the heater control temp selector. As the selector is moved from cold to hot, outside air is blocked allowing only heated air to enter the cab. If your flap isn't working properly, your heat could be mixing with a lot of cold outside air, making the heat output warm at best.
If your system is like mine, you should be able to see the flap once you remove the vent screws.
John24255
