Help! HVAC Heater Bypass Valve Broken

Help! HVAC Heater Bypass Valve Broken

Postby Pegman [OP] » August 19th 2013, 1:19am

Gents,

I'm towing in western Canada. Today I overheated in a small town. I've located a coolant leak at the HVAC bypass valve the valve appears to have cracked at an upper male stem and the top of the valve has separated from the bottom. I'll try to move 600 yards to a repair shop tomorrow morning.

Is this a common failure? Am I correct to assume the entire valve is supposed to be one piece? Is it possible that there is another problem that caused increased coolant system pressure?

Appreciate any help.

http://www.partsmonkey.com/en/catalogue/2004/chevrolet/astro-van/v6-262ci-4.3l-f-i-vin-x/heater-core
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Re: Help! HVAC Heater Bypass Valve Broken

Postby chevymaher » August 19th 2013, 1:40am

Yea it used to be one piece and they fall apart. Nothing is wrong with your van.
There are many on the site who bypass them.
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Re: Help! HVAC Heater Bypass Valve Broken

Postby Pegman [OP] » August 19th 2013, 1:52am

Seems like 6 or 7 lines coming from that valve. Can't imagine how I could bypass now. Hopefully tomorrows mechanic can do something. Thx
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Re: Help! HVAC Heater Bypass Valve Broken

Postby redfury » August 19th 2013, 10:47pm

Bypass by removing the two lines coming from the engine, don't worry about the others. you've got two for the front, two for the back, and the two that come from the engine to supply the system and return it to the engine.
A temporary fix usually becomes a permanent solution, therefore it does not exist.
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Re: Help! HVAC Heater Bypass Valve Broken

Postby godmachine81 » September 5th 2013, 2:21am

The valve is only there to keep the heater core from getting hot when you don't run the heater. Most of the heater cores have a flap over them though so when the heat is not on the flap is closed. This makes the control valve just something that causes more trouble than it is worth to me and most people on the forum. If you bypass it as chevymaher mentioned, you most likely aren't going to notice any difference in your heating/cooling situation (unless the flap on the heater core isn't there or doesn't work)

To do so just remove the plastic valve assembly altogether, and place the two lines that come from the engine (one on the passenger side intake, the other on the water pump) directly to the two hose fittings on the firewall. If you have the rear heat you should already have two "T's" before where the valve was. The T's should be going to your rear heater core unit.

You just have a return line and sending line to each heater core. It doesn't matter which way you run the heater core hoses it will work as long as the coolant goes in (sending) and comes back out (returning). Just make sure that the way you route the hoses provides full circulation for your coolant and you will be good to go. Hope that makes sense :)
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