Heater Core Repair or Replace? - ZR-1 Net Registry Forums

Shizap · 01-24-2023

Hey guys,
I recently discovered the heater core on my 1990 Zr1 was leaking. I just got it out and now I am trying to decide whether to replace it or have someone repair it. The aluminum replacement I bought looks on the cheap side and the pipes will need to be bent to make it work. I really don't want to ever have to do this job again. Is there a high quality replacement out there? Has anyone had success repairing the original heater core?

GOLDCYLON · 01-24-2023

Replace only. I would not try mending a 33 year old Heater core. While you are there you might want to replace the blend door actuator as it's a bear of a project to get in there

Dynomite · 01-24-2023

Quote:

Originally Posted by Shizap

Hey guys,
I recently discovered the heater core on my 1990 Zr1 was leaking. Is there a high quality replacement out there?

Quote:

Originally Posted by GOLDCYLON

Replace only.

As GOLDCYLON says...."Replace Only"

Post 135 - Replacing the Heater Core and Heater Hose Connection

Shizap · 01-24-2023

Thanks for the advice guys, I am just going to return the aluminum heater core and purchase the more expensive copper one from Zip corvette. Hopefully the fitment is better. Also, thanks for the great write up on how to remove the heater core Dynomite, it definitely saved me some time without having to remove the dash!

GOLDCYLON · 01-25-2023

Quote:

Originally Posted by Shizap

Thanks for the advice guys, I am just going to return the aluminum heater core and purchase the more expensive copper one from Zip corvette. Hopefully the fitment is better. Also, thanks for the great write up on how to remove the heater core Dynomite, it definitely saved me some time without having to remove the dash!

Cliff is the man !!!!! His solutions have saved many a ZR-1 owners time and given them the knowledge to take the projects on.

HAWAIIZR-1 · 01-25-2023

Quote:

Originally Posted by GOLDCYLON

Cliff is the man !!!!! His solutions have saved many a ZR-1 owners time and given them the knowledge to take the projects on.

I could not agree more with GC!! The info he has put together cannot even be put into words. I know I cannot thank him enough.

Cliff,
Since you have several years of Zs, have you needed to do the 95 and will it be any different if not removing the dash? I was going the cheater route this weekend and doing a bypass. I thought eventually I would repair when retired as I just dread this more than pulling the motor and installing new cams. Thank you. If I were still in Hawaii I would just bypass and forget it, but it would be nice to have heat here in Japan.

HAWAIIZR-1 · 01-25-2023

Quote:

Originally Posted by Shizap

Hey guys,
I recently discovered the heater core on my 1990 Zr1 was leaking. I just got it out and now I am trying to decide whether to replace it or have someone repair it. The aluminum replacement I bought looks on the cheap side and the pipes will need to be bent to make it work. I really don't want to ever have to do this job again. Is there a high quality replacement out there? Has anyone had success repairing the original heater core?

Best wishes with your replacement. You give me some encouragement and make it sound easy, but I can imagine it is a project no one ever wants to do even once. I bought a replacement over 20 years ago for my first Z and never needed it. I will dig it up and check the quality. I would like to have it pressure tested first. I hope you find a good one.

Dynomite · 01-25-2023

Quote:

Originally Posted by HAWAIIZR-1

Cliff,
Since you have several years of Zs, have you needed to do the 95 and will it be any different if not removing the dash

My Heater Core on 1990 (#3032) started leaking on floorboard passenger side So.......had to remove some carpet to get rid of antifreeze smell and just worked up under the passenger side dash (had been there before removing the CDM in another 1990 ZR-1).

I am assuming the 95' would be very similar.....except the CDM on 1995 is behind passenger seat

I did pull the passenger seat before pulling the heater core on a 1990 ZR-1

secondchance · 01-25-2023

Hey Cliff,

I have yet to read your write up on removing the heatercore but when I did a 92 Wazoo car, only thing I can think of to avoid pulling the dash was cutting the heater core inlet and outlet and splicing the inlet and outlet to a new heater core.
I ended up removing the dash and the whole thing took about 8 hours. At the end I was left with a plastic tube about the size of my thumb and three 7mm screws. I think the plastic tube probably was a connection to side window defroster vent on the edge of the dashboard.
Having replaced the heatercore once, I have been religious about replacing the coolant every two years.

HAWAIIZR-1 · 01-25-2023

Quote:

Originally Posted by Dynomite

My Heater Core on 1990 (#3032) started leaking on floorboard passenger side So.......had to remove some carpet to get rid of antifreeze smell and just worked up under the passenger side dash (had been there before removing the CDM in another 1990 ZR-1).

I am assuming the 95' would be very similar.....except the CDM on 1995 is behind passenger seat

I did pull the passenger seat before pulling the heater core on a 1990 ZR-1

Hey Cliff, Thanks for the reply. In theory it should be easier then without CDM there, but probably replaced with some other crap. I guess only one way to find out. I?ll take a peek under there when I install my stereo in a few weeks. Wish me luck.

01-24-2023	#1
Shizap Join Date: Oct 2020 Location: Coweta, Georgia Posts: 53	Heater Core Repair or Replace? Hey guys, I recently discovered the heater core on my 1990 Zr1 was leaking. I just got it out and now I am trying to decide whether to replace it or have someone repair it. The aluminum replacement I bought looks on the cheap side and the pipes will need to be bent to make it work. I really don't want to ever have to do this job again. Is there a high quality replacement out there? Has anyone had success repairing the original heater core?

01-24-2023	#2
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,153	Re: Heater Core Repair or Replace? Replace only. I would not try mending a 33 year old Heater core. While you are there you might want to replace the blend door actuator as it's a bear of a project to get in there __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

01-24-2023	#4
Shizap Join Date: Oct 2020 Location: Coweta, Georgia Posts: 53	Re: Heater Core Repair or Replace? Thanks for the advice guys, I am just going to return the aluminum heater core and purchase the more expensive copper one from Zip corvette. Hopefully the fitment is better. Also, thanks for the great write up on how to remove the heater core Dynomite, it definitely saved me some time without having to remove the dash!

01-25-2023	#9
secondchance Join Date: Aug 2006 Location: McLean, VA Posts: 3,703	Re: Heater Core Repair or Replace? Hey Cliff, I have yet to read your write up on removing the heatercore but when I did a 92 Wazoo car, only thing I can think of to avoid pulling the dash was cutting the heater core inlet and outlet and splicing the inlet and outlet to a new heater core. I ended up removing the dash and the whole thing took about 8 hours. At the end I was left with a plastic tube about the size of my thumb and three 7mm screws. I think the plastic tube probably was a connection to side window defroster vent on the edge of the dashboard. Having replaced the heatercore once, I have been religious about replacing the coolant every two years.