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  #1  
Old November 12th, 2019, 20:30
SeanSS SeanSS is offline
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Another heat problem 'thread'

Yep, im gonna be that guy tonight..





Got a heat problem.





99 Classic



I flushed the cooling system 4x including the heater core 4x as well.

This insisted of draining the system the first time, adding some type of cleaner from valvoline, running/driving the jeep, draining that, filling with distilled water, running/driving some more, emptying the water, filling with water again... You get the idea.



So, i KNOW this isnt my heater core.. I have plenty of flow, both of my hoses get piping hot, i think i have a possible blend door issue.. However... Ive read and read and read and i have read a whole bunch of stuff about the blend doing being manually actuated via a cable directly from the HVAC controls on the dash, mine is not this way. I have the electric actuator..



Here's some more good info... I can visually see the actuator rotating and i can visually see that the white/yellow plastic piece coming out of the heater box is also rotating. I hear a sound difference in air movement when i switch my heat/cool knob to cool or to heat.. I can hear a difference, however... I am getting the most slightest of warm air through my vents.


Tonight, i tried to remove the electric actuator, i got 2 of the 3 screws out, didnt think i could get to the 3rd one, after giving up and putting it all back together, i read on website that a swivel is needed to get the 3rd screw out. So maybe i'll revisit that tomorrow as i do have plenty of tools including the swivel.





Whats next?



Is it really my heater core? Im nearly certain i have plenty of flow in that area.. Ive flushed and flushed and flushed the thing and water definitely flows into one hose and out the other. Is there something else i am missing?



Could the water pump have some play in this?

Is there a separate area where the water pump pushes coolant
strictly for the heater hoses? Im not familiar with exactly how the

water pump operates other then that it circulates coolant throughout

the engine.. Im not aware if pushes coolant specifically through the

heater hoses from the thermostat housing or what.





Help me out here.. Its cold, i have SOME heat, but man... I should have a whole bunch more..





Thank you!
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  #2  
Old November 12th, 2019, 20:53
4x4JeePmaNthINg's Avatar
4x4JeePmaNthINg 4x4JeePmaNthINg is offline
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Re: Another heat problem 'thread'

what thermostat do you have and how old is it?

does the blower motor function?


the heater core is just like a small radiator. if water is going through it readily than so is heat, which goes back to your blend door/ or thermostat.
many times when the blend door fails itll get stuck on defrost as a default, is there hot air freely blowing under the windshield?
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  #3  
Old November 13th, 2019, 05:20
SeanSS SeanSS is offline
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Re: Another heat problem 'thread'

Thermostat was new when i did all the flushing, think it is a 195 degree stat.

My diverter works fine, i can change the air direction from the floor, to my face, to defrost and so on..
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  #4  
Old November 13th, 2019, 06:17
CJR CJR is offline
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Re: Another heat problem 'thread'

My 00XJ FSM suggests an initial flushing with the heater OFF so as not to clog the heater core with debris. After the head/engine/radiator are reasonably clean, with flushing & backflushing, then turn the heater on to flush/backflush it. If the heater core is clogged, it may take some more flushing/backflushing to clean it out.

Best regards,

CJR
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  #5  
Old November 13th, 2019, 06:26
Wattsman Wattsman is offline
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Re: Another heat problem 'thread'

Should you only flush once? Or should you keep flushing and backflushing a few times?
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  #6  
Old November 13th, 2019, 07:04
RCP Phx RCP Phx is offline
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Re: Another heat problem 'thread'

Quote:
Originally Posted by Wattsman View Post
Should you only flush once? Or should you keep flushing and backflushing a few times?
That would depend more on what you are using, some of the flush kits can actually make things worse if your heater/radiator core is already getting thin.
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  #7  
Old November 13th, 2019, 07:49
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Tim_MN Tim_MN is offline
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Re: Another heat problem 'thread'

Remove both heater hoses at the front of the engine. Use a garden hose to flush one hose then the other back and forth every 20-30 seconds for a few minutes total time.

Old coolant will precipitate silicon particles that like to collect in the heater core due to the lower flow rate or the confined spaces as compared to the rest of the engine.

Consider that the water pump fins are corroded resulting in low flow rate at low rpms.


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Quote:
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Tim MAY be 100% correct, but why would a person automatically pick him as the expert .....
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  #8  
Old November 13th, 2019, 08:45
Heavyopp Heavyopp is offline
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Re: Another heat problem 'thread'

I used a pump from harbor freight to set up a way to flush heater cores on 2 XJs
Using a 5 gallon bucket, you can set up your cleaning mixture and recirculate it through the heater core for as long as you want -- Both cleanings for me took an hour each

1st time I used a commercial coolant system cleaner -- second jeep I used an older box of dishwasher dish detergent, still had phosphorous in it -- I've heard you can use TSP too if you can find it anymore

Anyway, the Harbor freight pump runs off 12 volts DC, you need a bucket of Hot water and the hose connections and you can do this anywhere without the need for running water
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  #9  
Old November 13th, 2019, 15:04
SeanSS SeanSS is offline
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Re: Another heat problem 'thread'

The heatercore isnt plugged up. Again, i have plenty of flow through both hoses as stated above.
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  #10  
Old November 13th, 2019, 16:01
SeanSS SeanSS is offline
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Re: Another heat problem 'thread'

Ive got great general knowledge on automotive related stuff as far as i know. Im a gear head, drag racer, been around vehicles and engines since i could walk.

If this were as simple as a plugged up heatercore. I wouldnt be here asking for help.

I can remove the bottom hose that comes from the heatercore snd coolant oumps out of there at a high rate. Flow is not the problem.
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  #11  
Old November 13th, 2019, 16:06
SeanSS SeanSS is offline
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Re: Another heat problem 'thread'

The metal pipe that runs from the waterpump to the lower heatcore hose, are those prone to becoming blocked?

Or how about the water pump where that steel pipe threads into it, is that a known area that may become blocked? Im not familiar with what the inside of the waterpump looks like beyond that piece of pipe.
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  #12  
Old November 13th, 2019, 17:27
SeanSS SeanSS is offline
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Re: Another heat problem 'thread'

This is what i am referring to



https://www.youtube.com/watch?time_c...re=emb_ title
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  #13  
Old November 13th, 2019, 18:09
CJR CJR is offline
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Re: Another heat problem 'thread'

If your heater core is not putting out heat, then:
1, The water pump may be defective and not flowing coolant fast enough through the heater. Low water velocity (i.e. low Reynolds Number/laminar flow) degrades heater performance. A thick coolant boundary layer, at the inside tube circumference (i.e. laminar flow), reduces the overall heat transfer from the hot water to the air. A high coolant velocity (i.e. high Reynolds Number) provides turbulent flow with a much thinner coolant boundary layer at the inside circumference that improves overall heat transfer. Likewise, there are boundary layers in the air, at the outside circumference of the tubes, that also affect the overall heat transfer. Slower air flow has thicker boundary layers and lowers overall heat transfer, Faster air flows have thinner boundary layers and increases overall heat transfer.
2. The belt maybe slipping.
3. The heater core maybe clogged.
4. The heater tubes may have a build-up that needs to be removed by "rodding-out" the tubes after you remove the heater core. But if you remove the heater core, it's best to just replace it with a new one.
5. The heater door may not be allowing enough air (i.e. mass rate) to flow through the heater core and get warm.

Did you remove the thermostat before flushing?

Best regards,

CJR
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  #14  
Old November 13th, 2019, 18:10
SeanSS SeanSS is offline
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Re: Another heat problem 'thread'

Found the problem, ive got heat.





Thanks to those of you that tried to help, i gotter figured out.

Inlet pipe was plugged up somewhere between the inlet and the well, outlet.

Same thing that is described in that video i found, same thing i mentioned in post #11.
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  #15  
Old November 13th, 2019, 18:31
RCP Phx RCP Phx is offline
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Re: Another heat problem 'thread'

Quote:
Originally Posted by SeanSS View Post
I have plenty of flow, both of my hoses get piping hot, Thank you!
Your the one that said you had good flow!
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