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Has anyone changed a heater core out on a 79 F100 looking at the book it don't look to bad but if anybodys got any tricks it would be much appreciated thanks
I have found that it helps to undo the bolt that holds the lower right side of the dashboard to the cab. That lets you pull the bottom of the dash out enough to let the heater box slide out.
It's not too bad at all. I changed mine last year in my 77. I didn't unbolt my dash, but I can see where unbolting the dash would help with the process. It's just a matter of removing glove box, hoses, fan wires and control cables, unbolting from the firewall then working the housing out. I find a lot of leaves and gunk from 25 years of use, which I cleaned out. This really helped air flow after reinstallation. Took me a couple of hours.
[updated:LAST EDITED ON 15-May-02 AT 03:11 PM (EST)]Thanks guys im going to change it out this saturday i can see the dash bolt idea helping quite a bit thanks again -WIZ
Will probably take less than an hour. But loosening the dash is about the only tip i have aswell it helps alot. You may also wanna have some foam tape or weather striping to reseal the core and blower motor as your old stuff will most likely be shot. I hate when people use silicone gasket sealer to do this job. It makes it a real bugger if you have to take it back apart. One thing ive learned in my 13 yrs. as an auto. tech is new parts arent always good parts lol.
i just replaced my heater core in my 78 a few weeks ago and i will pass this little tidbit. i was following the book and i could not get the unit to come out as the dash kept it from moving far enough back to get the tubes out of the firewall. at this point i was pissed so i cut the tubes off and dropped the heater out. i did not know how i was going to get it back in after i changed the core but when i got the new core out of the box the tubes were about an inch shorter than the original one. that inch was all the difference in the world. it went right in and i didn't have to unbolt the dash (i was about to!). the moral is cut off the old tubes and remove the unit and then see if the new core has shorter tubes like mine did. good luck, hawkrod
having another hand to replace the plenum is handy, its a bit awkward.
As well, taking the whole thing out is the only way to change the blower motor, so while it might not be broken, if its original, you might want to put in a new one--but hey, its not my money
I agree with Blaine,with the unit out changing the motor is a case of "You Might As Well As". New motor cost me about 20.00. But I also had to change both. Just might save you from having to do this again.