Need help with Heater core replacement
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Joined: Mar 2023
Posts: 78
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From: Cape Coral
Need help with Heater core replacement
Just my luck, I have a small leak in my heater core and can't stand the smell and it is finally getting cold in south west Florida. I have the service manual and watched the very few videos on YouTube, I know it will be a PIA but I'm willing to try. Since GM doesn't make any of the AC parts anymore I need a good source for the heater core and all the seals and gaskets or anything I can substitute for the original seals. I hate to do a half *** job and try to put things back together as close to original as possible. I need a quality heater core if anyone knows where to get one I don't want to have to do this job twice. Also, my daughter uses my second car for work and I don't want to driver her to work more than a couple of days so I would like to have every part I need before I start. Any help will be appreciated.
Safety Car
Joined: Mar 2017
Posts: 3,755
Likes: 934
From: Orlando Florida
The C5 Parts Manual lists two different seal kits for the HVAC housing and blower. Kit #1, required when servicing the evap core is part # 52478813. Kit #2, required when servicing heater core, is part # 52478817. Both kits are listed as discontinued by GM, but I see that Topflight lists two apparently very similar kits, their Part #38364 listed as equivalent to the 52478813 kit, and then their Part #203973 -- NoT listed as equivalent to 52458813 or 52478817.
I thought Corvette Central and Ecklers both used to have seal kits, but CC doesn't list 1/10th of the parts they used to, and Ecklers apparently no longer handles C5 parts at all.
I thought Corvette Central and Ecklers both used to have seal kits, but CC doesn't list 1/10th of the parts they used to, and Ecklers apparently no longer handles C5 parts at all.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,360
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From: Cape Coral, Florida
Just my luck, I have a small leak in my heater core and can't stand the smell and it is finally getting cold in south west Florida. I have the service manual and watched the very few videos on YouTube, I know it will be a PIA but I'm willing to try. Since GM doesn't make any of the AC parts anymore I need a good source for the heater core and all the seals and gaskets or anything I can substitute for the original seals. I hate to do a half *** job and try to put things back together as close to original as possible. I need a quality heater core if anyone knows where to get one I don't want to have to do this job twice. Also, my daughter uses my second car for work and I don't want to driver her to work more than a couple of days so I would like to have every part I need before I start. Any help will be appreciated.
Racer
Joined: Jul 2011
Posts: 462
Likes: 122
From: Ozark Alabama
Did my heater core as a "while I'm in there precaution" and tried to use a rock auto FOUR SEASONS 90055 heater core. The flange that goes through the ac box physically would not fit through the hole. I ordered UAC HT399418C from rock auto and it worked fine. I also had trouble with the A/C evaporator core from Rock auto FOUR SEASONS 54567. The seats for the seals were cut differently so they would not seal, I ended up using GM GENUINE 1562692 from rock auto and everything works good now. This project turned in to a cluster F**k but I got it done and everything works good now. Remember Rock Auto has no, I mean 0 customer service. You can send stuff back and reorder another part but it takes a lot longer and you have to pay return shipping. The car is my daily driver but I am fortunate enough to have extra toys.
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Joined: Mar 2023
Posts: 78
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From: Cape Coral
Looking at the picture of the UAC HT399418C heater core the pipes are not even they are staggered, do the pipes rotate at the core connection? Did you replace the foam seals, the ones on the heater core look like they would disintegrate over time the ones around the evaporator look stronger. What did you seal the plastic case with?
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Racer
Joined: Jul 2011
Posts: 462
Likes: 122
From: Ozark Alabama
Looking at the picture of the UAC HT399418C heater core the pipes are not even they are staggered, do the pipes rotate at the core connection? Did you replace the foam seals, the ones on the heater core look like they would disintegrate over time the ones around the evaporator look stronger. What did you seal the plastic case with?
I don't remember about the pipes but they all lined up and worked well.
Race Director
Joined: Oct 2004
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Man!!! This is a bummer, because I need a new evap core for my A/C. As long as I'm in there, and considering my car is going on 24 years old with 140,000 miles on it, I think it'd be stupid not to have the heater core replaced too. None of this sounds good to me! I hate to think I'm gonna throw 2,500.00+ into it, and still have issues afterward.......
Thread Starter
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Joined: Mar 2023
Posts: 78
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From: Cape Coral
I'm considering doing the evaporator too but hate to change out a good one. The first time I replaced an evaporator it leaked worse than the original, had to put the original back in while I waited for a replacement.
Racer
Joined: Jul 2011
Posts: 462
Likes: 122
From: Ozark Alabama
Man!!! This is a bummer, because I need a new evap core for my A/C. As long as I'm in there, and considering my car is going on 24 years old with 140,000 miles on it, I think it'd be stupid not to have the heater core replaced too. None of this sounds good to me! I hate to think I'm gonna throw 2,500.00+ into it, and still have issues afterward.......