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Help with weird heater issue.

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Old Nov 16, 2013 | 05:00 PM
  #1  
The91XJ's Avatar
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From: Utah
Year: 1999
Model: Cherokee
Engine: I6 4.0L
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'96 Jeep Cherokee country 4.0

I'm not getting any hot air!

Here's where I'm at:
Brand new t stat and water pump. Flushed cooling system thoroughly. Water check valve seems to be opening and closing fine. BUT the two hoses going into the valve from the motor get really hot and the two hoses going from the valve to the heater core don't feel like they have any coolant running through them. Can the water valve fair internally causing no coolant flow into the heater core?

We also inspected the blend door linkage and that seems to be in worker order.

Any input or help is much appreciated. Its getting COLD in Utah!
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Old Nov 16, 2013 | 05:08 PM
  #2  
The91XJ's Avatar
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From: Utah
Year: 1999
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Also, when you change the temp from cold to hot the blower motor loses power and restrics air flow coming out of the vents..?
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Old Nov 16, 2013 | 05:23 PM
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highmileage's Avatar
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From: Bakersfield CA
Year: 1990
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have you verified that you have vac to the diverter valve, and yes they can fail. Also did you flush the heater core just by itself or with the engine?
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Old Nov 16, 2013 | 05:59 PM
  #4  
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From: Utah
Year: 1999
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Yes the valve has vacumm. I can see the arm movijg up and down when the heater control is switched on. When the flush was performed we flushed the whole system including the engine. The heater core was not flushed by itself. How exactly would I flush just the heater core?

Last edited by The91XJ; Nov 16, 2013 at 06:02 PM.
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Old Nov 16, 2013 | 06:09 PM
  #5  
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From: ☼ Blackhole Sun
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The best recommendation would be to throw that silly valve in the trash and plug the vacuum line.
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Old Nov 16, 2013 | 07:26 PM
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From: Riviera, Texas
Year: 1998 Sport
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Originally Posted by Turbo X_J
The best recommendation would be to throw that silly valve in the trash and plug the vacuum line.
This is the best thing to do. Get rid of the heater control valve all together. The manufacture got rid of them in the later years. The heat will be controlled with the blend door. Like Turbo X_J said just make sure to plug off the vacuum hose and you will be fine. Also try flushing the heater core in both directions several times.
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Old Nov 17, 2013 | 02:36 AM
  #7  
The91XJ's Avatar
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From: Utah
Year: 1999
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Ended up pulling the valve and it was stuck closed, bypassing any flow to the heater core. The heater core itself was full of dirt and sand of some sort. So we back flushed that, and replaced the valve with one from AZ for now. I now have a perfectly working heater! Thanks for the input guys
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