how hard to replace heater core?
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mschmidt10k
New Member
- Dec 10, 2003
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It's not that bad - the hardest part is getting the heater box out of the car. On my 67, it was a matter of:
- removing 4 nuts on the engine-side firewall,
- disconnect the two hoses from the heater box,
- disconnect the heater motor wires,
- remove glove box,
- loosen the two heater cables connected to the heater box
- remove one screw holding heater box to body
- pull out heater box, being careful not to mess up the interior paint
Once the heater box is out, there are a couple of clips holding it together - once you remove them, you should be able to access the heater core.
The Ford shop manual has more detailed instructions.
- removing 4 nuts on the engine-side firewall,
- disconnect the two hoses from the heater box,
- disconnect the heater motor wires,
- remove glove box,
- loosen the two heater cables connected to the heater box
- remove one screw holding heater box to body
- pull out heater box, being careful not to mess up the interior paint
Once the heater box is out, there are a couple of clips holding it together - once you remove them, you should be able to access the heater core.
The Ford shop manual has more detailed instructions.
69PaleHorse
Member
Well, not knowing what car you have, it's difficult to say. BUT, if it's a '69, let me tell you - you are in for a trip through Dante's nine rings of hell.
Just a friendly warning.
Just a friendly warning.
mozpony
New Member
what year on 65-66 you should change the hose's also as they go through the firewall and are connected to the core before the box is put back under the dash.
CochinoFilipino
Founding Member
You may as well replace the seals while you have the box out. I wish I had. http://www.mustangsplus.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=MPFMP&Product_Code=01209
dodgestang
Active Member
It looks like you have a 66 according to your garage profile.
This is how I do it:
Partially drain the coolant and unhook the heater hoses from the block
Then take out Glove box
unbolt the 4 nuts from inside the engine compartment and unplug the wiring harness (pictured on the left side)
Then take the hose from the defroster off the box and slide the control wires off their levers.
Look up where the passenger side fresh air vent is and there is a screw holding that in, unscrew in, then pull the wiring harness from the front of the box and pull...it will slide out and then down after the heater motor clears the fire wall.
Carefully remove it from the car pulling the heater hoses out with it and be sure not to spill anything
Put it on the workbench
And then pop all the clips off. The box is in 2 peices
Inspect the new core and compare it with the old to confirm it is correct
And then reassemble and install. If you chose to install a new foam set (which is a great idea put it in before you re-assemble). This will put new foam on the lip the core sits against for a better seal, on the moving doors too.
It really is easy on a 65-6
Shouldn't take more than an hour start to finish.
This is how I do it:
Partially drain the coolant and unhook the heater hoses from the block
Then take out Glove box
unbolt the 4 nuts from inside the engine compartment and unplug the wiring harness (pictured on the left side)
Then take the hose from the defroster off the box and slide the control wires off their levers.
Look up where the passenger side fresh air vent is and there is a screw holding that in, unscrew in, then pull the wiring harness from the front of the box and pull...it will slide out and then down after the heater motor clears the fire wall.
Carefully remove it from the car pulling the heater hoses out with it and be sure not to spill anything
Put it on the workbench
And then pop all the clips off. The box is in 2 peices
Inspect the new core and compare it with the old to confirm it is correct
And then reassemble and install. If you chose to install a new foam set (which is a great idea put it in before you re-assemble). This will put new foam on the lip the core sits against for a better seal, on the moving doors too.
It really is easy on a 65-6
Shouldn't take more than an hour start to finish.
I have a 69, and while I have done a number of cores over the years, it still isn't what I would call easy. If you're fan motor is behing all the stuff, like it is on my 69, replace the fan motor while you are in there.
Cars with AC are a whole nother animal. Try it on a smog maverick with air and a dash that cant be removed. Quite a picnic.
Cars with AC are a whole nother animal. Try it on a smog maverick with air and a dash that cant be removed. Quite a picnic.
oz
Founding Member
I changed the one in my '69 several years ago without removing the heater box (or dash pad)... I honestly don't remember how I did it but I remember standing on my head a lot and using a lot of wood shims to hold the case open far enough to wedge the old core out and the new one in... now that I think about it - I don't know how I pulled it off. I think I must have been able to remove one side of the heater case without removing the dash....
If you don't drive it in cold weather and it wouldn't bother you to not have it hooked up, you can just join the feed hoses together and bypass the core....
If you don't drive it in cold weather and it wouldn't bother you to not have it hooked up, you can just join the feed hoses together and bypass the core....
WORTH
Dirt-Old 20+Year Member
dodgestang, nice writeup. You forgot to mention to be carefull with the spring clips that hold the case together, if your rough you can break the tabs off the box.
Just a Hint;
I usually spread them by putting a screwdriver in each of the 2 slots and prying them together.
Just a Hint;
I usually spread them by putting a screwdriver in each of the 2 slots and prying them together.
Ozsum2 said:
A couple of cautions:
a. Remove hoses from engine side first then drain before attempting to remove heater box.
b. When removing heater box, pull disconnected hoses through the firewall to get sufficient room to work before attempting to disconnect the hoses from the heater core. If you wish to save the hoses, either cut short or remove from core. Some coolant is going to come out of the hoses so be sure to have a drip pan underneath the lines. Use a old bath towel under the drip pan just in case. When lifting the box out of the car be sure to hold the heater box and cores with the heater box nipples facing up. If you don't, you'll get a lot of coolant where you don't want it (all over the interior).
c. When separating the heater box halves be sure to remove clips carefully. If you just pry them off, some or a lot of the fiberglas comes off with the clip and then the clip has nothing to hang onto when you go to reassemble. If you do this then its either ingenuity or time for a new heater box...so be careful! If the clips go on to hard when reassembling, then lay them flat on concrete and using a small hammer hit them lightly on the arch. This flattens the arch and widens the clip. It goes on easier then but does not hold as tightly. The right touch with the hammer gives the correct result. Don't use clips that are either sprung or too flattened. You can get replacements at the Mustang parts store cheap. Its the box that's expensive.
d. If you want the heater to work well, then be sure to put a new gasket kit in it. About $20 for the kit. Plus a couple dollars more for some aerosol spray glue (needed to attach the gaskets and foam insulation).
e. Check the fan motor while the box is out. No sense of doing all this work and then finding out you need to replace the fan motor. The fan motor can be checked by simply connecting it to a 12v battery. No, it won't hurt to hold it in your hands when testing it.
f. Use a flat black aerosol paint to lightly paint the box while its out. It looks a lot better when a light coat of flat black paint covers the worn gray look that the box gets with age.
Good luck!
Jeff
