Heater Core replacement DIY - ZR-1 Net Registry Forums

SteveCS · 10-10-2023

Did the heater core on my car over the weekend, started out following some of the YouTube vids and ended up finding easier ways to get it done. Threw together a write-up if anyone needs it.

JT ZR-Won · 10-10-2023

Great info, thank you posting that!

Jay

Matt B · 10-11-2023

Thanks for sharing! I went through this some time ago. And I have to admit that I have absolutely NO idea how you managed to remove the heater core housing cover with that nasty tube in place. Congratulations you found a way!!!

In my case, even with every bit and piece removed and the hose loosened (I went the long run and did not cut the tube) it was next to impossible to pull that cover. Speaking about a 91. I had to get the tube out of my way in order to proceed.
To be clear: I didn't have any issue to access all screws. Easy going with all braces removed. But (on my 91) that hose is one single piece that runs straight from the heater core into the driver side footwell and fully locks the cover in. AND it has a nozzle attached to it that reaches into the heater core housing.

How did you overcome that? Don't get me wrong - I don't doubt you made it. Just want to understand how

VideoCapture_20231010-221641.jpg VideoCapture_20231010-221624.jpg

Corvettes White · 10-11-2023

Nice first post. Welcome to here.

George

SteveCS · 10-11-2023

Quote:

Originally Posted by Matt B

Thanks for sharing! I went through this some time ago. And I have to admit that I have absolutely NO idea how you managed to remove the heater core housing cover with that nasty tube in place. Congratulations you found a way!!!

In my case, even with every bit and piece removed and the hose loosened (I went the long run and did not cut the tube) it was next to impossible to pull that cover. Speaking about a 91. I had to get the tube out of my way in order to proceed.
To be clear: I didn't have any issue to access all screws. Easy going with all braces removed. But (on my 91) that hose is one single piece that runs straight from the heater core into the driver side footwell and fully locks the cover in. AND it has a nozzle attached to it that reaches into the heater core housing.

How did you overcome that? Don't get me wrong - I don't doubt you made it. Just want to understand how

Attachment 19913 Attachment 19914

Good catch, and I missed it on the write up. Full disclosure - I didn't know about that before removing as all of the other how-tos remove the tube with the box. The "nozzle" as you call it does detach, and you can pull the duct away enough to get on it from behind.

Further disclosure - I'm a car audio guy, I've never met a dash I couldn't reverse engineer so what seemed intuitive to me may be a nightmare for everyone else.

Matt B · 10-12-2023

Haha, I'm a car audio guy, too. We have skills and can bear pain levels other guys can't.
But that nozzle particularly drove me CRAZY when trying to get it back in place. Removal was okay as things tend to simply fall off at a certain point. But reinstalling it was a challenge.

I wish I could have seen how you made it and learn [emoji106]

Corvette95 · 10-19-2023

Great post. As I understand it, the 94-96 C4 heater box is easier to access than the early ones and if you have to do the heater core, it is recommended to replace the early box with the later box. Mirrock Corvettes had a big write up about it. I have a later box ready just in case.

BlackZR1 · 10-28-2023

Thanks SteveCS, Saving for future reference.

HAWAIIZR-1 · 10-29-2023

Thank you Steve CS. I need to do this soon on my 95. I?m sure I?ll owe you a few beers for this if you?re ever in Hawaii or Japan. [emoji1360]🤙🏼

Sent from my iPhone using ZR-1 Net Registry

HAWAIIZR-1 · 10-29-2023

Quote:

Originally Posted by Corvette95

Great post. As I understand it, the 94-96 C4 heater box is easier to access than the early ones and if you have to do the heater core, it is recommended to replace the early box with the later box. Mirrock Corvettes had a big write up about it. I have a later box ready just in case.

I am praying you are correct for my 95. I don?t know the difference, but I need to remove the bypass hose and just do this soon.

Sent from my iPhone using ZR-1 Net Registry

10-10-2023	#2
JT ZR-Won Join Date: Aug 2021 Location: Bradenton, FL Posts: 138	Re: Heater Core replacement DIY Great info, thank you posting that! Jay

10-11-2023	#3
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 523	Re: Heater Core replacement DIY Thanks for sharing! I went through this some time ago. And I have to admit that I have absolutely NO idea how you managed to remove the heater core housing cover with that nasty tube in place. Congratulations you found a way!!! In my case, even with every bit and piece removed and the hose loosened (I went the long run and did not cut the tube) it was next to impossible to pull that cover. Speaking about a 91. I had to get the tube out of my way in order to proceed. To be clear: I didn't have any issue to access all screws. Easy going with all braces removed. But (on my 91) that hose is one single piece that runs straight from the heater core into the driver side footwell and fully locks the cover in. AND it has a nozzle attached to it that reaches into the heater core housing. How did you overcome that? Don't get me wrong - I don't doubt you made it. Just want to understand how VideoCapture_20231010-221641.jpg VideoCapture_20231010-221624.jpg __________________ ZR-1 #638/1991 Last edited by Matt B; 10-11-2023 at 02:30 AM.

10-11-2023	#4
Corvettes White Join Date: Dec 2003 Posts: 477	Re: Heater Core replacement DIY Nice first post. Welcome to here. George

10-12-2023	#6
Matt B Join Date: Jan 2021 Location: Beautiful Bavaria Posts: 523	Re: Heater Core replacement DIY Haha, I'm a car audio guy, too. We have skills and can bear pain levels other guys can't. But that nozzle particularly drove me CRAZY when trying to get it back in place. Removal was okay as things tend to simply fall off at a certain point. But reinstalling it was a challenge. I wish I could have seen how you made it and learn [emoji106] __________________ ZR-1 #638/1991

10-19-2023	#7
Corvette95 Join Date: Jan 2006 Location: Decatur, AL Posts: 1,119	Re: Heater Core replacement DIY Great post. As I understand it, the 94-96 C4 heater box is easier to access than the early ones and if you have to do the heater core, it is recommended to replace the early box with the later box. Mirrock Corvettes had a big write up about it. I have a later box ready just in case. __________________ Corvette95 Registry and Forum (*************) 1989 C4 Conv Wht/Gry Auto Hardtop Top Flight SOLD 1995 C4 Coupe Purple/Blk 6 Speed 1989 C4 Conv Wht/Red Auto SOLD 1996 C4 Conv Black/Tan Auto SOLD 1994 C4 Coupe Wht/Blk SOLD 1995 C4 ZR-1 White/Gry #278 Dual Dunn Head SOLD 1986 C4 Coupe Black/Red 4+3 SOLD 1990 C4 ZR-1 Red/Red #0454

10-28-2023	#8
BlackZR1 Join Date: Aug 2015 Location: Pittsburgh, PA Posts: 152	Re: Heater Core replacement DIY Thanks SteveCS, Saving for future reference. __________________ Roger 1990 ZR-1 #2699 Black on Black 15,000 miles Full-time secondaries, 4.10 gears, C-beam plates, ported top end

10-29-2023	#9
HAWAIIZR-1 Join Date: May 2010 Location: Japan Posts: 3,587	Re: Heater Core replacement DIY Thank you Steve CS. I need to do this soon on my 95. I?m sure I?ll owe you a few beers for this if you?re ever in Hawaii or Japan. [emoji1360]🤙🏼 Sent from my iPhone using ZR-1 Net Registry __________________ Craig "ZR-1 NO KA 'OI" "ZR-1 ICHIBAN" 1995 #228 Black/Black with Dunn Heads ZR-1 owner since September 2003 ZR-1 Net Registry Founding Member #0074 NCM Lifetime Member #2048