bigapplephx

I feel warm/hot air flowing out of my vents, when the heater vent valve is off. If I installed a ball valve in the return water line to the heater, to shut off the water flow, would that put undue pressure on the line, resulting in possible bursting??
I only intend on doing this during the Arizona summer.

ronjenx

Are you saying you don't have air conditioning?

By "heater vent valve", do you mean the rotary temperature selector?
Even here in Maine, when the ambient temperature is high, warm air comes out of the panel vents.
Warm air in the cowl vent = warm air out the panel vent.

Freewill

Same problem here. I think it is typical of the Wrangler. No matter how long or hard the fan runs the vents stay hot.

I'm not sure its the heater core, which would mean a shut-off valve won't help. I kinda think it is just engine heat warming up the ducts. I'd like to be wrong on this because not much can be done if its engine heat.

Can't see why the shutoff valve would hurt anything. The heater hoses are a bypass of the main cooling circuit. If water can't pass through the heater it just runs through the rest of the cooling system.

Please post if you install the valve and it works. Its really dumb to hafta run the AC compressor just to get the vents down to outside air temp when its 60-70 degrees out. BTW, there are electric valves available (Sporlan) if you're into convenience, but its a lot cheaper to try a manual valve first.

JK-Ford

I havn't noticed this situation in my Jeep. But I have seen this problem in my wife's car. She actually figured out a way to correct the problem though. I'm no expert on the inner workings of the A/C system. So I can't explain why this works. I just know that it does. Set your system to "COOL" and turn it on. Then just simply turn it OFF. Seems to work every time.

m998dna

In addition to the solution above, maybe look at the blend door(s)... they could be hanging up.

ytee

You can install valves in the the heater hose lines to block off the heater core. It will make the interior a bunch cooler in the warm months. Be aware if you make this mod that you need to install a bypass (Tie the two heater hoses together) because our cooling system bypasses all the time. If you don't install the bypass it will cause you to build pressure and have a leak. It is simple to do just put a valve in each heater hose and install a tee in each heater hose on the motor side of the valves that you install. Then tie the two tees together with a vale in that line also. Just make sure when you close the two valves you open the valve in the bypass.

Chris

Freewill

Good info. Thanks!!!

For the bypass, maybe a pair of 3-way valves (well, actually 2-way with 3 connections) would make a nice solution? I've used these in similar setups. When the valves are "off" to the heater, they are "on" to a bypass hose between the valves, and visa-versa.

If someone could describe how our heater system bypasses all the time I'd be a grateful reader. This may explain why there is so much heat in the system when the temp control is set to minimum.

ronjenx

People with plugged heater cores don't have pressure problems. The water stops flowing to the core, and they get no heat.

A single valve in one of the heater core lines will give the same result, if you think it's a mod that actually needs to be made.

The water pump is a centrifugal pump. If the output is blocked, the water simply goes around inside the pump along with the impeller blades.
Stopping the flow through the heater core circuit does not create the need to have a bypass.