Replacing the Heater Core in a 1974 Mustang II Ghia

KingDoom · 10-14-2008

Has anyone ever done this in a Mustang II similar to my model and year? I saw nice tutorial on a Fox Body Mustang, but I'm thinking my car won't be THAT much of a hassle (I hope). I have the Haynes repair manual and a new Heater Core, I just need to know the steps. Should I take my car to a shop to have them drain the coolant first? Do I need to discharge the AC? How much of the dash needs to be disassembled before I can get to the old core? I am not planning on removing the entire heater box if it is not completely necessary.

spdjnky_42 · 10-15-2008

I did mine years ago, and its pretty much the same as doing the one on my 89. It is a real pain, but can be done and you dont have to pull the heater but it will be a fight to remove and replace the core. Took about 6 straight hours in the car w/ the dash in you lap!

spdjnky_42 · 10-15-2008

Shouldnt have to mess with the ac

mustangiighia · 10-16-2008

When I did mine I took the whole heater box out it was just easier that way cause of all the clips and screws on the thing. And it only took me about 2 hours.
I took the glove box out so I had more room and the dash off so I could stick my hand down there.
Its not that difficult just remember to drain the coolant and put some plastic down so coolant doesn't get everywhere.

mustangiighia · 10-16-2008

Oh and I meant the dash pad not the whole dash.

KingDoom · 10-16-2008

I just finished replacing my core, thanks everyone for your help. Ghia, how did you remove your glove box? The bottom plastic didn't want to budge. The screws by the front wouldn't unscrew and i couldn't see a good way to remove whatever was underneath.

mustangiighia · 10-17-2008

There are screws underneath the dash and inside the glove box but thats about it. You just have to find the screws. If you get a manual it should tell you.

KingDoom · 10-17-2008

The screws inside wouldn't unscrew.

I have a new problem now, my blower doesn't turn on and burns my heater fuses when it's plugged in. What could have happened when I put my car back together? I tried it once before I installed the rest of my dash and it worked, but now when I rehooked the hoses it doesn't. Is this a common problem?

mustangiighia · 10-18-2008

That sux that they won't come out. But the only thing I can think of that might be wrong is either a loose wire or a broken wire that is touching some metal or just that your blower motor is going up or the resistor for the motor.