How to safely bypass leaking heater core? - ZR-1 Net Registry Forums

jpalmer1717 · 01-16-2019

Well, the title says it all. I just dumped a bunch of money into headers and a reprogrammed chip, just to have my heater core spring a leak. I cannot do this job and I don't know anyone around that would (if anyone knows someone near Asheville NC, lemme know). So I will have to live without heat, which sucks. But can some nice person out there in the zr1 world explain exactly how to bypass (from the engine side)? I don't even know how to make the hose connections on something like this. Just hose clamps? Thanks in advance....
-bummed owner of '90

Karl · 01-16-2019

Mine is broke also. The bypass is simple. You will need to make a u connection and just reroute the fluid back and bypass the heater core.

Of course this is on the passenger side firewall behind the overflow tank.

It's too cold outside for me to work on the car. I may just bypass also.

Pulling the dash seems to be a major p.i.t.a.

Dynomite · 01-16-2019

It can be done from under the Dash...……..you have to remove the CDM. And there are a couple tricks

Post 135 - Replacing the Heater Core and Heater Hose Connection

Moonlk · 01-17-2019

Just go to the hardware store and buy some elbows and pipe nipples to make a u-shape and unhook the hoses from the heater core to loop the coolant. Did this a couple of years ago when mine blew the core on the first drive of the spring. Ran it like that all summer and then changed the heater core over the winter. Honestly though if I knew how much a pain in the a** it was to change I would have not bothered.

Young1 · 01-18-2019

Buy pizza, BBQ and beer and go up to the WAZOO garage. They are experienced.

WARP TEN · 01-18-2019

Quote:

Originally Posted by Young1

Buy pizza, BBQ and beer and go up to the WAZOO garage. They are experienced.

Good idea--they are close to you. Also Marc and Bob Haibeck have done many heater core fixes if you wanted to ship yours up to them near Chicago. www.ZR1specialist.com.--Bob

rkreigh · 01-21-2019

if the heater core turns out to be leaking get ahold of Gordon Killabrew and talk to him about the trick to make the swap out easier.

just unhook both hoses going into the heater core and make a U shaped loop back to bypass in the meantime.

getting to the hoses on the firewall is a bit ugly, take the recovery tank and dump it into a bucket after removing bolts to make access easier. Just takes a couple of minutes.

01-16-2019	#1
jpalmer1717 Join Date: Sep 2018 Location: Asheville Posts: 62	How to safely bypass leaking heater core? Well, the title says it all. I just dumped a bunch of money into headers and a reprogrammed chip, just to have my heater core spring a leak. I cannot do this job and I don't know anyone around that would (if anyone knows someone near Asheville NC, lemme know). So I will have to live without heat, which sucks. But can some nice person out there in the zr1 world explain exactly how to bypass (from the engine side)? I don't even know how to make the hose connections on something like this. Just hose clamps? Thanks in advance.... -bummed owner of '90

01-16-2019	#2
Karl Join Date: May 2013 Location: Chicago Posts: 977	Re: How to safely bypass leaking heater core? Mine is broke also. The bypass is simple. You will need to make a u connection and just reroute the fluid back and bypass the heater core. Of course this is on the passenger side firewall behind the overflow tank. It's too cold outside for me to work on the car. I may just bypass also. Pulling the dash seems to be a major p.i.t.a. __________________ 1993 ZR-1 #211 Yellow On Beige Beast #2 1992 ZR-1 #427 Black On Black Sold 1985 L98 Blue On Blue Sold

01-16-2019	#3
Dynomite Join Date: Aug 2009 Location: South Dakota/California Posts: 3,790	Re: How to safely bypass leaking heater core? It can be done from under the Dash...……..you have to remove the CDM. And there are a couple tricks Post 135 - Replacing the Heater Core and Heater Hose Connection __________________ Left Clickable links -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 01-16-2019 at 09:55 PM.

01-17-2019	#4
Moonlk Join Date: Nov 2011 Location: Saskatoon Canada Posts: 47	Re: How to safely bypass leaking heater core? Just go to the hardware store and buy some elbows and pipe nipples to make a u-shape and unhook the hoses from the heater core to loop the coolant. Did this a couple of years ago when mine blew the core on the first drive of the spring. Ran it like that all summer and then changed the heater core over the winter. Honestly though if I knew how much a pain in the a** it was to change I would have not bothered. __________________ 1991 ZR-1 #1158 Dark Red Metallic/Saddle 1993 LT-1 White/Red Guts SOLD 1986 L98 4+3 Red/Grey SOLD

01-18-2019	#5
Young1 Join Date: Sep 2016 Location: Ocala, FL Posts: 881	Re: How to safely bypass leaking heater core? Buy pizza, BBQ and beer and go up to the WAZOO garage. They are experienced. __________________ Steve Young 1991 ZR-1 Quasar Blue Metallic/Black #729 Second Owner 1991 ZR-1 Dark Red Metallic/Black #2040 SOLD 1990 ZR-1 Dark Red Metallic/Saddle #1670 SOLD Double your happiness.....complain half as much.

01-21-2019	#7
rkreigh Join Date: Jan 2004 Location: Alex VA Posts: 1,087	Re: How to safely bypass leaking heater core? if the heater core turns out to be leaking get ahold of Gordon Killabrew and talk to him about the trick to make the swap out easier. just unhook both hoses going into the heater core and make a U shaped loop back to bypass in the meantime. getting to the hoses on the firewall is a bit ugly, take the recovery tank and dump it into a bucket after removing bolts to make access easier. Just takes a couple of minutes. __________________ 95 390 LPE ZR1 (505 rwhp) LSV = Lingenfelter Super Vette Twin Turbo 2003 Z06 (800 RWHP)