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How do i clear the heater core hoses to try and fix heat?

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Old 09-16-2014, 08:50 PM
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Post How do i clear the heater core hoses to try and fix heat?

My floorboards arent wet and i dont lose any coolant, yet my heat barely gets luke warm.

I have done tons of searching on how to backwash the heater core hoses from both sides or something, but after looking at all of those posts, i still have no idea what anybody is talking about.

Im deffinitely not a newbie, but i dont do much with any cooling system, so if anybody could explain in detail/give me some steps/show me a picture or anything, i would really appreciate it.

Last winter sucked, i still shiver some times thinking about how cold it was driving in the morning. Dont wanna go through that again.
Old 09-16-2014, 09:13 PM
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Disconnect the heater hoses at the water pump and t-stat cover. Stick a garden hose in the heater hose that was connected to the water pump and flush. Stick the garden hose in the other heater hose and flush. Repeat several times.
Old 09-17-2014, 08:25 AM
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VERIFY.

How hot is each heater hose at the firewall in comparison to the radiator hoses when the Jeep is warmed up?
Old 09-17-2014, 08:30 AM
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Originally Posted by cruiser54
VERIFY.

How hot is each heater hose at the firewall in comparison to the radiator hoses when the Jeep is warmed up?

Not to thread hijack, but I'm about to do
The same thing with my girlfriends 96xj. Heat is horrible In the winter. Was planning on bypassing the heater junction valve, replacing thermostat with 190* and flushing the core.

I remember feeling the heater hoses on her xj last year and the temp to touch felt the same going in to heater core as it did coming out.... Cannot verify if it was equal to the larger coolant hoses..
Old 09-17-2014, 08:34 AM
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Originally Posted by mitch500
Not to thread hijack, but I'm about to do
The same thing with my girlfriends 96xj. Heat is horrible In the winter. Was planning on bypassing the heater junction valve, replacing thermostat with 190* and flushing the core.

I remember feeling the heater hoses on her xj last year and the temp to touch felt the same going in to heater core as it did coming out.... Cannot verify if it was equal to the larger coolant hoses..
Good points.

The heater control valve can cause issues. There is NO downside in removing them and plugging their vacuum line. They are actually prone to imminent failure and large loss of coolant. Who needs that?

Having the correct thermostat is also important.
Old 09-17-2014, 09:51 AM
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If both heater hoses at the firewall r really hot to touch (about the same as the top rad hose) and the heater is still weak, the problem is most likely with the blend door inside the HVAC box under the dash.
Old 09-17-2014, 05:16 PM
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Originally Posted by djb383
If both heater hoses at the firewall r really hot to touch (about the same as the top rad hose) and the heater is still weak, the problem is most likely with the blend door inside the HVAC box under the dash.
Correct.

And here's where to adjust it.
Attached Thumbnails How do i clear the heater core hoses to try and fix heat?-blend-door-cable.jpg  
Old 09-17-2014, 06:31 PM
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Originally Posted by cruiser54
Correct.



And here's where to adjust it.

Any procedure to adjust it? Or is it pretty self explanatory once I look there....

I'm going to give this a shot when I get home from work... Maybe it will save me from the work I mentioned before
Old 09-17-2014, 06:33 PM
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Originally Posted by mitch500
Any procedure to adjust it? Or is it pretty self explanatory once I look there....

I'm going to give this a shot when I get home from work... Maybe it will save me from the work I mentioned before
Pretty self explanatory. There's a stop for the lever.

Undo the clip holding the cable housing and and move as needed.
Old 09-17-2014, 06:44 PM
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Make sure you don't have these issues either

Fan speed switch:

How do i clear the heater core hoses to try and fix heat?-forumrunner_20140917_184240.png

Rear of hvac panel with chunks broken off:

How do i clear the heater core hoses to try and fix heat?-forumrunner_20140917_184332.png
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