: Help me bypass my hetaer core

03-08-09, 12:25 PM
Can someone be so kind to give me some info on how to bypass my heater core on my 99' Catera please? Its leaking pretty good inside the car. thank you

03-08-09, 05:24 PM
simple behind ur engine there are two lines that go to the fire wall(psnger side of course) one for coolent in and one for out just get a U and connect from one to the other and BYPASS compleate

03-09-09, 02:50 AM
yea actually i know that Ariza034, i guess i was hoping for someone to tell me/us a quick fix under the passenger side dash that may leak Besides the heater core because, im not about to start tearing the dash out or who knows what. thanks Ariza034 im gonna have to bypass it and get it over with.

03-09-09, 12:52 PM
I just replaced my heater core and it's a big pain.

The plastic shell on the input side (passenger side) of the heater core is probably breaking down and cracked. Not much way to patch it, and its such a pain to get to, so it's probably quicker to just bypass it. That'll get ya a few months.

I noted the aftermarket replacement had a more substantial plastic end-cap than the one I removed.

03-10-09, 02:07 PM
looking at those 2 lines going into the firewall, both the other ends seem to be on a mechanism ill assume is the heater actuator. If they are both going to that and looping in the mechanism then there must be a 3rd going into the firewall that i cant find. ill look again....

03-11-09, 10:05 AM
the two lines that go into the firewall feed directly to the heater core straight in / straight out. The heater control valve is on the outside of the firewall behind the intake plenum.