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I just completed the removal of my old heater core. It was not that hard, thanks to the info I found on this site. Before I ask my questions, here is what I found and used to remove mine (i.e. the 'how to') for those who are looking to do it themselves:
1) I cannot see obvious leaks when inspecting the old core. I know it leaks. It started by a little smell of coolant, and suddenly a big waterfall of coolant leaking from the firewall on the engine side. I am lucky, only a few drops on my carpet. Like I said, the core looks old, but likely not original because it is not that bad. The thing is that I cannot find an obvious hole / rust / burst / etc. The hoses are completely dry, so I am excluding the possibility that they leaked at the connection with the core. I will replace the core, but is there something else that could have leaked in the firewall and I did not see it? I don't want to disassemble everything again soon to replace something else that I could have done now.
2) In addition to the 'wet' parts discussed above, what would be your recommendations for seals and gaskets? Online, I see <Firewall Heater Core Gasket>, <Heater and AC Box Seals Set>, <Heater Core Seal>, <Heater Box Foam Washer Set>, and more... What do I need. Nothing I removed can be salvaged (or even recognized...)
3) I am interested in your recommendations for: Where and what should I buy (brand, quality, kit, etc? Note that I live in Canada -> it would be a plus if the store is in Canada, or if the US store delivers to Canada. But I prefer having your trusted store, even if it is in the USA and does not ship to Canada as I have a US mailbox about 90 minutes from home.
4) Less important: I will also look for a Chassis Service Manual shortly. If any of you have one to sell (CD would work too), please let me know.
Long post, but I think all the info is there. I have no experienced with car repair, hence my use of picture to explain what I mean. Car is W/O AC.
Thank you in advance.
Last edited by RedFive; September 23rd, 2017 at 04:01 PM.
If you want to see where the heater core leaks, cap off one side and run about 10#s of water or air pressure through it. The gaskets needed depends on the condition of your old gaskets and how far your going to tear into it. Most often times you can reuse all the old stuff and just put the box back on the firewall, retighten nuts and attach hoses.
There is no other way for coolant to enter the cabin but through a leak in the core.
The reason I am asking what I should buy is because the seals are in pieces, or were not installed. So I cannot go with <what was there>. Nothing was holding together when I removed the inner box. And it was caulk that replaced what looked like the first image I posted (well... I think that is what is it supposed to be...).
So what should be installed? That spongy thing next to the core (the first image), a seal that goes between the inner box and the firewall (second image), a seal between the firewall and the "back plate" (on the engine side), the fourth image is heater box foam washer - what is that for? Also, the first link posted above suggests to <get a heater seal kit so you can replace the seals on the diverter doors, this will assure you do not get heat in the summer when you don't want heat>. What is that? Any link?
Last question: the core itself... aluminum or brass (if I can find one)? Any specific manufacturer? I saw <Spectra> on a few sites including Rockauto but could not find the seals and gasket there. Then this site (https://www.early-birds.ca/parts_413_558_562.html) has the core and the gaskets...
Again, all the questions are just to make sure I do it properly, like those with experience would do it. I have none and looking to learn.
I ordered all the parts, received everything I asked for. One issue: the core I ordered is smaller than the old one. The new one is likely correct: all the online store lists the same size for my car, and this is what I received. However, it is not the same size I had in the car first... Is it possible that my heater box is not year/model correct? That would explain why the new core is smaller than the old one. But is that really a possible solution? Someone way back then would change the inner box and all the connections just because he could not find a proper heater core? Unlikely...
See pictures below. Advice? I am thinking of making an adapter (sheet metal) to go behind the core to reduce the hole (seen in picture 5) and make it fit with the new core.
Picture 1: heater box (you can see the gasket that will touch the firewall, but it is not fixed yet).
Picture 2: Old heater core (never mind the missing pipes, I cut and used them to bypass the heater core so I could flush my coolant system while waiting for the parts).
Picture 3: Similar to picture 1, with gasket that goes between inner box and heater core.
Picture 4: New heater core.
Picture 5: New heater core, focus on lower part. You see it does not fit and there is a gap not covered by the core.
Picture 6: New heater core, focus on top, without the clip attaching the core to the heater box.
Picture 7: Same as picture 6, with the clip. You see that the bend in the clip no longer works with the new core.
Last edited by RedFive; October 6th, 2017 at 02:52 PM.
Your original heater core is the correct size and material. You purchased a generic aluminum replacement that is a bit shorter. Not a real issue as long as it does not flop around in the heater box. You may want to fab a bracket for the end that is short and modify the clip at the tube end to hold it in the correct position so that both the tubes and the heater box studs will pass through the firewall.
Thanks for the answer. I was expecting the replacement part to be exact same dimensions. If I chose a 'generic one', was there a 'specific one' somewhere. All the places I looked had the same size (9-1/2" high x 6-3/8" wide x 2-1/2" deep) and that is smaller than what I had.
I can fabricate a bracket as you suggested. Because the core is shorter (as seen in picture 5 above), I will also have a 1/16 sheet metal cover the 'hole' in the box and will cut a smaller hole that fits the new core. Basically, that will act as some sort of reducer.
Progress will be slow, but I will update as it moves forward.
I would venture the demand for an exact fit heater core for a 66 cutlass has dropped off some over the years.
I would guess the size unit you received will service many cars.
ideally we would all like to receive an exact fit replacement, but the reality is we are lucky to be able to still get new parts that can be made to function as the original in many cases
the correct size copper/brass heater cores, whether for non ac or ac cars have all but disappeared from the auto parts stores. I deal with this often as I restore these parts. 64-67 abody factory ac cars as well as 67-72 gm trucks have this issue especially. Why they cant get the dimensions right over there in China, I dont know. Hate having to alter the brackets. Got pretty lucky last week though as Auto Zone actually had a brass copper heater core for a 65 Chevelle heater box I was restoring. Damn thing fit like a glove. The other option is to take it to your local radiator shop and have them swap your tanks onto a new core. It will fit perfectly then. Some of my customers demand this as they want their original Harrison tanks. Around here its $100 to have this done.
I would venture the demand for an exact fit heater core for a 66 cutlass has dropped off some over the years.
I would guess the size unit you received will service many cars.
ideally we would all like to receive an exact fit replacement, but the reality is we are lucky to be able to still get new parts that can be made to function as the original in many cases
I just expected an exact replacement, without thinking any further. But that explanation makes total sense.
Originally Posted by banny
The other option is to take it to your local radiator shop and have them swap your tanks onto a new core. It will fit perfectly then.
That I did not know. (Hey remember: newbie here!). I guess it is too late now that I used one of the pipes to connect the two hoses and bypass the core to perform a rad flush while I was waiting for parts. I will know better next time...
Here is the bracket I built. It can be removed if a different size heater core is installed later. Thoughts? Comments?
Picture 1: Showing gasket between heater box and reducer plate (plate not in picture). Also showing core retainer clip in original position.
Picture 2: Showing reducer plate (gasket is under). Also showing the new bracket (U-bracket) and core retainer clip moved to the U Bracket.
Picture 3: New heater core in place. (Missing the clip at the pipe side - need to fab that).
Picture 4: Close-up on U-Bracket and core retainer clip. I will put thread locker on the two bolts to make sure they do not loosen up.
Questions:
1. Because the new heater core is in aluminum, is there a danger that the clip in picture 4 makes damage to the tank if there is too much pressure?
2. Should I have a gasket between the reducer plate and the heater core? I think I do, but would like to have your opinion.
3. I still need to put make sure the heater core is now free to move up and down. Can I just wedge or use spray adhesive to hold some cork / rubber / foam?
Thoughts and comments would be appreciated before I make this all 'official' and re-install everything.
I was busy lately, so the replacement had to wait. I am now done. I proceeded exactly as described above. Because the original core was longer but also wider, I used some of the gasket/foam that came in the kit but that I did not use (i.e. for the blower motor replacement, which I did not do) to prevent the new core from moving sideways (the new clip prevents it from moving up and down, as shown in the pictures).
All went well to reassemble everything. No issue accessing the fifth nut on the firewall side. I had a leak at the water outlet (I also change the thermostat). To fix it, I use some Permatex (form-a-gasket). Test drive was successful: engine Temp is centered at 180F and heater blower provide hot air.
Thanks to those who provided guidance. Much appreciated.
September 23rd, 2017, 01:47 PM
