Tremo

Yo guys. I have an 88 IROC and the heater core is starting to cause windshield fogging on cold days, but there is no wetness on the carpet under the thing. Must be a small leak.

Anyway, I read the tech article on replacing the core, and I was wondering, how long should it take? 1 hour? 2 hours?

Any special tools required?

Thanks!

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Patience.

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azvolfan

If there are no wet spots on your carpet I can tell you it's just a matter of time.

If you've never done it before, expect it to take you 3-4 hours. It's tedious and difficult to work under the dash, but not impossible. Patience will be key.

azvolfan

As far as toos, standard sockets and wrenches is all you need. Maybe some Quater inch drives and shorties might help under the dash.

The top screw on the heater box will be an issue. Take off the dash pad and take out the passenger side speaker. You might be able to get the screw out that way. I have big fat hands so I had to unbolt the dash and pull the dash out about 3 or 4 inches. It helped. The dash did not have to come all the way out.

Some people have trouble getting the new heater core hard lines through the fire wall. Before you try, when you have the old one out; hold it up to the new one and look at the old hard lines. Adjust the hardlines on the new heater core so they are the same apporximate angle and distance from each other as the old ones. Then try to get the new ones through the fire wall.

Good luck. Post your progress.

black89ws6

The biggest hassle is getting the dash pulled back far enough to work on it. If you've been up in the dash before, and know how all that comes loose, that will speed you up a lot.

I'll second what the other guys have said. 3+ hours for the first one. A guy doing a repeat could probably do it in 2.

Get a u-joint for your 1/4" ratchet and short extensions. It will help reach everything.

Tremo

I've had the dash pad out before to replace the speakers, but never pulled out the dash itself.

I also have big hands and arms, shoot, maybe I'll have to get my wife to help.

Now, my car has aircon, will that complicate things?

Thanks!

black89ws6

Not really. Most of the AC stuff is on the front side of the firewall.

BruceEmbry

I have replace the heater one time on my 82 Bird.
You do not have to take the dash off.

Remove the Hush Panel on the passenger side. There will be an access panel on the bottom of the Heat/cooling box.
Edited on June 18th 2005,
a) Remove the ECM!

b) Remove the trim panel at the bottom of the dash. Removeing this panel help getting access to the top screw of the heater box access panel. There are five screws that must be remove to be able to remove access panel. After the five screws are out, gently shift the access panel to the right and down. When you get the access panel off, you will see the heater core.

1) Drain the coolent
2) Remove the hoses under the hood at the firewall.
3) Remove two or three screws that hold the core in place and carefully remove it out(can't remember how many screws).
4) Now comes the hard part is getting the new core in place.
Aligning the heater core pipes to go back though the firewall will be the hardest part of the job... I place some long bolts in the pipe to help with alignment.

5) reassemble everything back and please don't forget to put all seals back in place.

PS, I never removed the dash panel when I did this.

Airpak

What is the hose on the left called? My coolants leaking underneath my car and it seems to be because of the hose. Theres coolant on the bottom side of the hose if I rub my fingers against it. So I'm guna order a new one and see, just wondering whats the name for the left side one that goes into the firewall. Is this a common problem with the hoses?

Thx.

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BruceEmbry

Hi al,
I wish I han't responded to this thread. I think my heater core read this thread, and it blew the past week. Had to order a new one, so I getting an AC Delco OEM part.

My expericance has been that parts purchase though Auto-Zone and Advance Auto are second rate. I remeber that I replaced the heater core about 10 years ago. I do regular maintainace on my car, for example the coolent is flushed out and replace every two years or 24,000 miles. I have order an OEM replacement AC Delco from www.rockauto.com. Ordered on Monday and arrived yesterday.

BruceEmbry

Hi all,
I in process of replacing the hearter core. Like I said above, the dash does not have to come loose. Once I got in there I remember the trick. REMOVE the ECM, after that there is more the suffienant room up in there to get to the scews on the top of the access panel.

black89ws6

Do you mean you didn't even have to loosen the dash and pull it even a few inches out?

BruceEmbry

Yes!

black89ws6

That is awesome. I wish I had thought of that the last time I changed out a heater core.

Crusin' 1980's

what is the part number for the heater box (non-AC) from AC Delco?....is it that same thing as if i ordered mine from GM? thanks

BruceEmbry

Don't know, go to www.rockauto.com

matt3383

Im not sure if the camaro is any different than a firebird with this but it took me maybe 1 hour tops, and that was having to run back inside a couple times for extensions. I agree that the hardest part of this whole thing is getting the damn thing to line back up in the holes when reinstalling.... well that and getting the old hoses off was kinda a pain in the ***.

bjordan

I had no problem lining up the (second) new heater core. Try this:

Mount it in the little bracket, and put it most of the way in under the dash. Go around and stick your finger through the firewall and into the end of a pipe, so you can just pull the thing into alignment and partway through the firewall with your finger. Then, go back under the dash and push it the rest of the way in. It hung a little on the hinge that closes the flap, but after getting past that it pops right into place.

The first replacement I got did not fit because the pipes angled wrong and were too far apart to get through the holes. If I did it again I'd just get the OEM core.

bjordan

attachment trouble

bjordan

Maybe this will save someone some time when removing the heater box. First pic is the screw after after removing the cruise control module and bracket. (84 TA L69 w/AC).

Attached Images

screw.jpg (41.0 KB, 626 views)

bjordan

This pic shows removed CCM bracket and tools. I didn't have a 12" 1/4 extension, so I taped a 7mm socket on the end of a long philips screwdriver. A telescoping magnet was useful for getting the screw started on reinstallation.

HTH someone.

Attached Images

tools.jpg (29.7 KB, 575 views)

John 89 Formula

I just did this in my '86 a week ago, replaced the entire hvac box,
as well as the core

I had to pull the dash almost completely out. I put the new box in and the heater core leaked. Fortunatley it was just a broken solder joint, I repaired it myself.

Replacing the core itself took about an hour.

I found a flexible 1/4" nut-driver to be very handy.

Tremo

Heater core replaced. I bought the replacement from www.radiatorexpress.com. It works good enough and fit correctly. Yes, the top screw on the heater box was nasty to reach. Did not have to pull the dash, only the kick panel, dash pad and pass side speaker.

The original core was leaking a tiny bit where one of the pipes enters the tank. The solder joint wasn't complete. No other leaks in the core. I cleaned it up and re-soldered both pipes where they enter the tanks, so I guess I now have a spare core.

Also, to reach the hose clamps on the firewall, it was necessary to remove the ignition coil.

LupusMaximus

I'm having some heater core blues atm, could use some help.

OK so I went through the hassle of takin everything apart, I can see the heater core through a plastic casing attached to it. I took out all the bolts and it is loose, so the next step I assume is to disconnect the hoses from the firewall.

Problem: Which hoses do I remove? I'm not all to familiar with the layout and it's a cluttered mess in there. Also, does having air conditioning require any additional steps?

It's a 1990 305TPI iroc with A/C.

Please reply if u have any suggestions

John 89 Formula

The two hoses go into the firewall on the passenger side, about 5 or 6 inches below the base of the windshield right next to the ac unit.

LupusMaximus

Ok those must be the ones, I'm fighting with em right now. 15 years of stuck on goodness. Even with my small scrawny hands I think Im gonna have to remove the ignition coil.

Thanks for the reply

nadster

Heh, I see I'm not the only one this month with the same small leak

-Nad

Tremo

It was necessary to remove the coil on my car in order to access the hose clamps at the firewall.

OK, so everybody, where was the leak in your core? Mine was where one of the inlet tubes solders to the tank, the seam was leaking. I fixed it with adding some more solder.

John 89 Formula

My heater core was not actually leaking, it was the whole hvac box I had to replace. My heater core was damaged in the process, cracked a solder joint.