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Replacing Heater Core in 1972 Olds Cutlass Supreme/ A/C not blowing through vents
I'm trying to replace my heater core in my 1972 olds cutlass supreme. I wanted to know the level in difficulty and did I have to remove the entire dash to get to it or could I just remove the glove compartment box. Also, pictures would be appreciated. Thank you.
Another issue is my A/C works but it doesn't blow out the vents but blows down at the bottom of the dash any suggestions?
It's not as much difficulty of the job to do, it's the time consuming pain in the but it is to do. Removing the glove box liner, side panel and peeling the carpet back a little. The Vent box can be a pain also to get out between the center console if you have one. Taking the seat out helps a lot also (The first time I used a 2x12 out the door and a 5 gal bucket to prop it up for me to lay on) There are plenty of Threads with pics on just this subject start to finish. I bet with the CSM and sticking your head under there you'll be able to get the vents working, it's either a vac or mechanical lever problem with one of the doors no moving.
I suggest that you find a 100% compatible copper/brass heater core.
The replacement ones don't fit well and are usually made of aluminum.
It is a fairly involved job - CSM has the entire picture.
Agreed. The new aluminum ones are terrible. The outlets are slightly off, and they are marginally smaller. If It'd known earlier, It'd have taken it apart, and sent my original out for repair. It's a small pinhole on the tank.
The CSM, at least for non-ac cars, is almost useless. It mentions nothing about the glove box. Removing the seat is certainly a requirement, unless you have a garage the size of the taj majal.
The inner fender also has to be removed, which is project in itself. And while it's out, you might as well clean/polish it. And it doesn't go back in easy.
You will also love some insulation from removing the box inside. Not sure it it'll actually matter, and I didn't know what to replace it with. Also, probably a good idea to blow air through the core and have a jug on the other one, just to remove what's in there, so it doesn't go all over the carpet.
You'll most likely need a second set of hands to get the box back in, especially if you have a console, otherwise you'll risk scratching up the console.
I have done this many times and never removed the seat, glove box insert, or the fender liner.
I am small enough to lay on the floorboard in front of the seat, but not everyone can do that. Since the seat comes out very easily it's probably worth removing it.
The heater box will come out from below the dash without removing the glove box insert.
As for the fender liner, there is that one bolt that has to be accessed. The first time I replaced the heater core I removed a bunch of the fender liner bolts so I could reach behind it to access the bolt, then I didn't put it back afterwards. I figured there were enough fasteners so that one wouldn't matter. The heater box never fell out with that one missing, and it made subsequent heater core replacements a LOT easier.
Here is a thread on my experience with the heater box. If you have a bench seat and no console, then you should be able to do this fine with the seat in. I only had access through the drivers door when I did it and it worked out... I did not have to worry abou tthat hidden nut as I never put it back on when the evap box was installed. https://classicoldsmobile.com/forums...tml#post362172
As for not blowing out the vents, check all the vacuum lines. You can check them and the air doors easier when the heater box is out. If all those are good, as well as the can on the firewall (above evap box with two hoses on it), the control valve on the control head could be bad.
There is a vacuum diaphragm in the box under the dash. if it is bad or has no vacuum the air will not blow out the top vents. To my knowledge, nobody makes the diaphragm.
Last edited by redoldsman; Mar 14, 2016 at 10:39 AM.
I have done this many times and never removed the seat, glove box insert, or the fender liner.
I am small enough to lay on the floorboard in front of the seat, but not everyone can do that. Since the seat comes out very easily it's probably worth removing it.
The heater box will come out from below the dash without removing the glove box insert.
As for the fender liner, there is that one bolt that has to be accessed. The first time I replaced the heater core I removed a bunch of the fender liner bolts so I could reach behind it to access the bolt, then I didn't put it back afterwards. I figured there were enough fasteners so that one wouldn't matter. The heater box never fell out with that one missing, and it made subsequent heater core replacements a LOT easier.
Agreed! I'm 6' 4", it was hard for me to lay on the floor board to do it. Removing the lines that run from the HVAC selector we hard for me and had to be done on the driver side.
Yes, I took your advice and left that one bolt out. I'm glad I did.
Originally Posted by Fun71
I agree, but where do you find a copper/brass one these days?
It'd have my original rebuilt. If it happens again, I'll send it out, or it'll go with the car when I sell it. If I was the OP, It'd take it apart, send the original out for repair, and replace it when it comes in. Not worth the hassle of the new ones, and having to bend the tubes and possibly breaking the new one.
Man it was years ago but I got a copper/brass replacement one (as suggested on here), Think I got it from Summit or NAPA. The only thing I did was take the bracket off the old one that spaces the tubes apart and soldier it onto the new one.
AHH the infamous WTF is this not coming out Bolt! Good memories...
It'd have my original rebuilt. If it happens again, I'll send it out, or it'll go with the car when I sell it. If I was the OP, It'd take it apart, send the original out for repair, and replace it when it comes in. Not worth the hassle of the new ones, and having to bend the tubes and possibly breaking the new one.
Thank you all for your help. I am a newbie at this and trying to do somethings on my own to reduce costs and gain experience. I have two new heater cores (I don't know how that happened) that I have had in storage for about 7 years never used I hope they are still in good condition. I have attached them below. Are these the non-brass ones you were referring to?
Best Quality Replacement Heataer Core for a 72 Cutlass?
Pretty sure I need to replace mine this season.
Got some funky fogging last couple of times i tried to turn on heat or defroster.
No obvious leaks under the dash, but it looks like maybe a tiny little seepage against the firewall.
Looking to get something that is not flimsy or plastic.
These three “look” fairly original - anybody have any recent experience with any of them?
Be aware that many of the resellers are using old pictures of copper-brass when the part they sell is actually aluminum. I ran into this last year when buying a heater core and I could not locate a copper-brass one.
Be aware that many of the resellers are using old pictures of copper-brass when the part they sell is actually aluminum. I ran into this last year when buying a heater core and I could not locate a copper-brass one.
The new one seems to have fit quite nicely into the car. The tubes coming through the firewall were a little longer, and they did not have a brace between the two of them them, as the original did. Not sure why they cheap out and leave that off. Maybe so that it can go in more than one application?
So of course, as soon as we tested the new heater core, the Heater Control Valve springs a leak....Ugh....That will be the weekend project.
ddd777 how involved was this project? What steps did you have to take to remove your old heater core to replace it with the new one? Do you need any sealant around the necks the come through the firewall?
ddd777 how involved was this project? What steps did you have to take to remove your old heater core to replace it with the new one? Do you need any sealant around the necks the come through the firewall?
Pretty involved, but I think it is completely do-able with a moderate skill level.
Because of my lack of working space, and crazy work schedule right at the time it failed, I had somebody competent do it for me. It took them 4-5 hours.
They did not replace any of the crumbling foam on the ductwork, so I will need to go back in and do that when I get the A/C up and running again.
I don't recall if they used a sealant, but that would make sense. I'll go take a look this evening and report back if I can see anything.
Pretty involved, but I think it is completely do-able with a moderate skill level.
Because of my lack of working space, and crazy work schedule right at the time it failed, I had somebody competent do it for me. It took them 4-5 hours.
They did not replace any of the crumbling foam on the ductwork, so I will need to go back in and do that when I get the A/C up and running again.
I don't recall if they used a sealant, but that would make sense. I'll go take a look this evening and report back if I can see anything.
Ok thank you. I was thinking about having a shop to do it initially and was quoted $300 (Is that a fair price in your opinion). Then I decided to try and see if I could do it myself but I don't want to get in over my head.
Ok thank you. I was thinking about having a shop to do it initially and was quoted $300 (Is that a fair price in your opinion). Then I decided to try and see if I could do it myself but I don't want to get in over my head.
If they know what they are doing, that sounds fair to me.
This is a really detailed overview of the procedure: https://classicoldsmobile.com/forums...tml#post362172
Take a peek and see if it is at your comfort level.
I think that if your car does not have A/C it is going to be easier, in that the front of the box may just come off, instead of needing to be completly removed along with the glove compartment (but don't quote me on that, not 100% certain)
Best Quality Replacement Heataer Core for a 72 Cutlass?
Ended up getting a (brass and copper) Heater Core from Summit
