Bypassing heater core

jeffnoel

Founding Member
Aug 31, 2002
1,638
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Clovis, CA
My II is a fair weather car only so is there a downside to bypassing the heater core other than the obvious? The reason is I think my core has a leak and since it's an AC car it's just way too much work to replace it for now.

Jeff
 
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About the only things I can come up with is that your cooling system capacity would be decreased slightly. I don't know how much more fluid would be held between the heater core and the hoses, but it would be some. The other is the ability to turn on the heat to help cool off your car. Also if you are using an electric choke that recieves it's signal from one of the heater hoses.

I would suggest making sure that you purge all the fluids from the core when you bypass it. You don't want old antifreeze and water sitting around in there even if it does need replaced as it can run down on other things and start or add rust.
 
Well, if you're half as dumb as I was back in high school, it could get you about killed!!! LOL

You just reminded me of a time about 15 years ago when my old Cobra's core started leaking, so I just looped the two long hoses together temporarily until I got another heater core.
Later, I had a buddy in the car and floored it until I had to slow down for a stop sign. Only the car didn't slow down! :rlaugh: The darn hoses had gotten hung up in the throttle linkage somehow, and while I'm giving it all I have on the brake pedal, my friend is trying to put the car in neutral to no avail. We're already past the stop sign, and the car is revvinng at about 6 grand by the time he get's the tranny out of drive and I get the bright idea to turn the key off. :D Funny stuff!

I know this isn't the response you wanted, but when I remembered it, it just made me laugh!
 
T0BASC032 said:
Well, if you're half as dumb as I was back in high school, it could get you about killed!!! LOL

You just reminded me of a time about 15 years ago when my old Cobra's core started leaking, so I just looped the two long hoses together temporarily until I got another heater core.
Later, I had a buddy in the car and floored it until I had to slow down for a stop sign. Only the car didn't slow down! :rlaugh: The darn hoses had gotten hung up in the throttle linkage somehow, and while I'm giving it all I have on the brake pedal, my friend is trying to put the car in neutral to no avail. We're already past the stop sign, and the car is revvinng at about 6 grand by the time he get's the tranny out of drive and I get the bright idea to turn the key off. :D Funny stuff!

I know this isn't the response you wanted, but when I remembered it, it just made me laugh!

dam, Brian. Thats some serious stuff!!! :( :nonono:
 
When I bypass it I will just connect a short hose between the inake and the water pump. There's no way what happened to you would happen with this setup as I wont have two long hoses bouncing around the engine compartment. This will also clean up the looks under the hood for car shows with less clutter. And my Holley's e-choke doesn't get a signal from the heater so no problem there. So the only downside I see is a little less cooling systen capacity, which should be no problem as long as the cooling system is working properly.
 
"Water Wetter"

I did just as you are talking about. It does make the car run a little hotter, so I put in a cooler thermostat, and added some stuff to the coolant called "Water Wetter" (avail. at Auto Zone and Advance, probably elsewhere). It claims that it lowers your coolant temp by up to 20 deg. It seems to work very well for me. Engine runs consistantly at 180, But my interior still gets toasty on hot days for some reason? :shrug:
 
jeffnoel said:
My II is a fair weather car only so is there a downside to bypassing the heater core other than the obvious? The reason is I think my core has a leak and since it's an AC car it's just way too much work to replace it for now.

Jeff


I have done it serveral times just a short hose on the water pump and intake

The only down side is rainy season windows fog up they clear better with heat.

plus the other stuff about the coolant level and cooling ability are nominal

Replacing the core is really not that much work once its done AZ has them for 39.00 last time I checked lifetime warrenty.

2 bolts on the side 2 on the top drop the steering column in the seat
(taking the drivers seat out will help provide more clearance or remove the steering wheel) mark and remove all vacumm lines going to the heater box, one cable and fan power wires, remove the nuts from the firewall engine side.

ps my AC is not hooked up so you will have to remove the AC lines.

WOW Maybe it is alot of work I have done it so many times (3) its cake now

just dreaded