How difficult is it to replace the heater core in a 1977 F-150 with factory air??

Troy

 

You probably will have to remove the glovebox to get to everything, but not too bad. If the evaporator is outside the firewall in the engine compartment, it's not much different than a non-ac truck. Also, if the blower motor goes through the firewall from the cab side, you may want to replace it now, while everything is apart.

 

I have a 1975 F350 with A.C. that I replaced the heater core in. I don't think there is any difference between them as far as the heater cores go. You'll have to do everything from inside the cab. It took me about 2 1/2 hours.

First, put on some of your favorite music. Have some good lighting. The A.C.evaporator is on the inside of your truck. You have to access it from the cab. You don't have to remove the glove box. Remove the plenum from the firewall under the glove box to to get to the evaporator. Mark and remove the wires connecting to the sensor switch. Be careful of the sensor wire going into the evaporator coil. Remove the sheet metal screws holding the evaporator in place. Then you should be able to pull and lift the evaporator at the bottom out of the way enough to get to the heater core without disconnecting the A.C. hoses. Now you have access to the heater core. Remove the hold down straps from the heater core. There are two straps, one on top and one on the bottom held in with sheet metal screws. Remember which is which and orientation as they are different. After the straps are removed the core should come out without too much trouble. (Heater hoses should already be disconneted). It should slip out between the evaporator and the frame. Install the new core in reverse order. It's tight working in there but you can do it. If you want to replace the blower motor, now is the time to do it. I didn't replace mine. Good luck.