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!

JamesC

iTrader: (5)

Patience.

JamesC

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.

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).

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.

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.

theshadowmonkey

haha, must be a cali thing. my 84z just dumped all of my coolant into my passenger seat last week. i simply cut the hoses off at the firewall since they wanted pull off and connected the hoses together. but now i know the easy way to put in a new core. thanx for the tips guys. oh yeah, and i have big hands but didnt need to take off the ignition coil to reach the clamps...

LupusMaximus

Ya I finished the heater core replacement, I am looking to refill my coolant, that is drained.

My only concern is that there is no coolant in my heater core, so I can't just add it.

Will typical engine burping work? Should I keep filling until engine opens up and takes coolant in and pushes air out? I had a buddy say to take off where the thermostat connects with the engine.

Just wondering if burping the coolant from the rad cap will prevent airlocks?

LupusMaximus

Posting to a previous message.

My heater core failed on the opposite side of the hoses, the right edge of the core was leaking

tom3

No need to bleed or burp the system, it will push through the core in a very short time with no problem, just top off the radiator and put some extra in the surge tank.

kurfbird

iTrader: (24)

Just did mine last night.

Thanks for the great info. Job probably took 3 hours. 1 hour was cleaning up the anti freeze from the carpet. Mine was leaking on the edge by the metal lines.

One day smelled Anti freeze next day had a puddle on the floor.

Glad I have a second car

Bruce

USN Retired

DIGI

I have an 86 camaro base model and i'm doing a heater core on it for the first time i have the cover for the heater box off but i can't get the heater core out i've removed the 4 screws that i can see and it still seems to be catching on something that i can't see. Am i missing something or do i just have to give a lil tug?

Xophertony

you have to give it a little tub. when i did the one on my GTA i had to bend the heaterbox slightly. good luck.

DIGI

alright thanks i got the heater core out without bending the box too much but the new one just doesn't wanna go in i'm thinking i just have to wiggle it and have some more paitence lol but if you have any tips again that would help thanks

John 89 Formula

Have a friend try and guide the two pipes through the firewall from the outside while you work inside.

DIGI

ye i tried that but i'm having troubles getting the actual heater core into the heater box i tried reinstalling the old one and it fit fine i made sure they were the same size and everything but it still won't go in....

ratchet698

Ok I am a lil confused. I have A/C on my 80 Berl. Does it (the AC box)have to come off to access the lower clamp? some say yes some say no. Can it all be done from under the dash/glovebox? I thought seeing as I should install new hoses at the same time I could pull it with the old hose right thru and attach new hose feed it back thru. I cannot see the clamp on the bottom hose but can see the top one.

codemystirl

I noticed my window fogging in my 92 camaro and a slight dampening in the passenger floor, so i ordered the heater core the next day. Picked it up for about $25 at Napa. It took me about 3hrs to install it, but i was pretty hesitant with everything that i did. I do not see how someone could install one without pulling the dash out at least a little ways. Anyways thats my story.

JamesC

iTrader: (5)

An FYI from an old post:

https://www.thirdgen.org/forums/tech...e-82-86-a.html

JamesC

redteamgo2000

i just changed mine, it was leaking on the bottom tube of the core itself. took about 45 min. no dash removal and no hassle with the tubes through the firewall. my g/f guided them through as i pushed. everything went awesome but by no means do i want to do it again.

ddayhawk

i really hope you guys are right about not removing the whole dash. mine has been slightly leaking since july, had the heater core since then but just 2 weeks ago after the waterpump went it decided to leak all over the place and flood my interior.

any other suggestions for this replacement?

tom3

Started smelling antifreeze just the other day. Shouldn't have read this post maybe? But I got down to the core by the method above, didn't move the dash. Pulled the cover and the speaker/bracket, stood outside the car and looked down through the windshield to get that top bolt out. Sure enough my core was wet at the top and bottom. Ordered the AC/Delco from Rock Auto for $55 complete. Now for the part I hate, draining coolant and removing those hoses. So far it hasn't been a bad job compared to others.

John 89 Formula

Get a couple pairs of vise grips and pinch the hoses closed then you won't have to drain the system.

ddayhawk

well i wasnt so lucky i had to remove most of the dash to get to that top screw. but luckily when the heater core went 2 weeks ago i just made a bypass from the radiator to the engine so i didnt have to deal with closing off the hoses since they were already off.

now my fluid has been rust brown ever since i got a rebuilt motor and new radiator. anyone know why this is? i got it flushed a few times but hell it still wont go away.

tom3

For reference the AC Delco core part number for my 88 is either ACD# 15-60034 or GM# 52479879 in group 8.854. Rock auto part number d15-60034.

classiciron

Hi,

Just replaced a heater core in my 90 R/S. I want to thank everyone for your helpful posts. I hope to be a help to someone else. I found you only have to remove lower dash panel, computer and plastic frame that holds computer, a box that is bolted to housing that holds heater core with two screws (don’t know what it is called) it is on lower right corner wires going in, I unbolted it and left it hang by wires. You have to remove this stuff to reach top bolt on heater core cover to start it back in to reinstall this bolt. You can reach this bolt for removal with a quarter inch socket with one medium length extension and one short length extension put together, (if you do not have them go out an buy them) I am not kidding I used Craftsman. You will need them for the rest of job too. To remove this top left bolt maneuver wrench between heater core cover and dash and with your right hand line up socket on bolt, this is fairly easy. I spent probably one hour trying to remove this bolt another way, got this tip from my service manual. To reinstall this bolt start it in by hand. The best tip I can offer is to line up heater core tubes to fit holes in
firewall. To do this I found it is best to leave the frame for the heater core off while you line these tubes up. I purchased a GM core and it had to be bent several times to fit, be careful bending tubes. My new core both tubes loosened in tank, had to go get them resoldered at radiator shop. I feel it was a bad solder job from beginning. Radiator shop told me that there are only two manufacturers in the country. So I would say get the best price from wherever. Radiator shop put a lot of solder on tubes to make strong.
Hope this helps.


Dennis

Gramps

iTrader: (1)

the nice thing about these third gens is that you dont need to remove the dash to get to the heater core, unlike every other GM ive encountered. and whats even better is that thers many different ways to do it. if you have a firebird, you can just remove the glove box thingy and you have ful access to it. camaros, you can remove the dash pad and reach or you can go from the lower dash cover and reach upwards. my job is the easiest, the prev owner cut out the dash to put his CD changer in, so i got a hole perfectly located so its a 15-20 min job to replace my heater core. its kinda a pissoff until you need to access that area and then its a godsend.