How to safely bypass leaking heater core?

[jpalmer1717]

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]

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]

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]

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]

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

[WARP TEN]

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]

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.