heater core replacment?

[pro-flo72]

how hard is it too replace a heater core ?i have a 72 ac truck and really need some help with this . i dont even know where to start inside the cab or under the hood any help would be great

[shuttermutt]

It's not the worst thing you'll ever do, but if you don't have patience, it'll be close! I don't know how different 72 is from 68, but on my truck I had to crawl under the dash, find the 5 (or was it 6?) studs around the box that ran through the firewall, get under the hood, remove the nuts that correspond to the studs, drain the radiator, pull the hoses, scream, curse, cry, beg the old core out, put the new core in and do it all again in reverse.

It took a buddy of mine and I about 4 hours total on a cold, rainy day to get it all worked out. Now that I've done it once, I'd say it's about a one-man, 2 hour job for a truck with A/C. Funny, that's the first core I've ever had go out on any vehicle.

[CUSTOM/10]

I just replaced my heater core this weekend. First of all make sure you get a heater core thats a direct replacement. Some of the after market cores have a larger tank on ea. end, and the brackets that have to go around the tank won't fit. So if your getting the core from a local parts store, remove it and the brackets and take them with you to make sure it will fit. Or you can order on from a board member that is aware of the issue so you'll get on that fits.

Removing the core should all be done from under the hood unless someone has stripped out the holes in the firewall and put nut and bolts through. Removing the inner fender makes it easier but isn't necessary. Drain your cooling system down, disconnect the hoses, unbolt the heater box and gentle start prying the box away from the firewall. Go easy or you may brake the box. Once you get it free there's a damper cable behind the box that needs to be lifted off of a post on the damper then your free to twist and turn until you find the correct position to get it out. Getting the cable back onto the post can be a real pain in the A$$, and may be easeir with someone helpping you. Just reverse the process for the install.

Have fun.

[shuttermutt]

Sounds like you've just done the non-A/C job, CUSTOM/10. My '68 has factory A/C and there's no way the core would've come out from under the hood. There's just no physical hole large enough to do that. Mine had to come out from under the dash and I'm fairly sure it's that way for all A/C trucks.

[CUSTOM/10]

You right !!! Mine is a none A/C truck. I didn't notice the ac until I read your reply. Sounds like the ac trucks must be a different animal.

[sactoC10]

I replaced mine out of necessity in August (it was leaking) and it does have to come out from under the dash. You'll need to remove the glove box to access some of the screws, etc... Since I was trying to locate the leak in the process, I also removed the bolts around front box under the hood.

It can be a VERY frustrating task, but it is not a difficult one, if that makes any sense. All you are doing, in simple terms, is removing the two hoses, pulling the core and insterting the new one...put it is getting the darn thing out the simply sucks.

I called my local parts store ahead of time to make sure they had one, removed mine, then took it with me to be certain what they were giving me was right. I'd suggest you do the same.

Make sure to replenish the coolant before firing things back up.

[72moneypit]

I replaced mine a few months ago. The hardest part, in my opinion, are two studs that go from under the dash into the engine compartment, on the bottom of the HC box. The nuts for these two studs are incredibly hard to get to, short of removing the wheel well. In my case, I pulled out the Dremel and cut a 'U' in the plastic around the studs from inside the cab. Since there are 3 or 4 bolts that secure it to the firewall, I didn't think I was harming anything.

Probably not the best way to go, but since I'm no mechanic and have limited patience, it worked well for me. I now have both heat and AC, and no coolant in the cab, so I'm happy. And, if I have to replace the heater core again, it'll be a snap.

[shuttermutt]

A lot of people either don't put those nuts back or drill a hole in the inner fender to get to 'em.

[pro-flo72]

thanks guys but does anybody have any pictures or diagrams?

[sactoC10]

Sorry, but when doing this job, there's not much motivation to break out the camera!

[shuttermutt]

Yeah, I'm afraid I can't help much with pictures either. It's a pretty self-explanatory job, though. All you've got to do once you've drained the coolant and disconnected the heater hoses is to figure out how to get the big, black box directly underneath your glove box out of there without using a Sawzall or dynamite.

Seriously, though. Give yourself plenty of time, take it slow and easy, keep your parts organized, and you'll be fine. If you run into problems, just shout back. Sounds like several of us have done this recently/frequently enough to be able to help you through.

My tip? Don't forget to put the A/C relay back on the big, black box BEFORE you put the big, black box back in place. Getting that sucker back on with a little screwdriver ratchet gizmo was a pain in the butt! Oh, and you may want to consider replacing the heater blower resistor while you've got everything torn apart. Most parts stores don't have 'em, but they can be had from vendors on the Internet. Just order one while you're ordering the new glove box insert you're bound to destroy!