Weak Heater

CopterDr

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Hi from Missouri....folks, I have a 2002 Limited 3.7. The heater is not real hot. I've flushed the core, installed a new radiator and hoses. Gets fairly warm setting still, but once moving down the road, it's temped at best.
Any info would be greatly appreciated.
Thanks
 

tommudd

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Did you also replace the thermostat
if not get a MOPAR works way better than those "zone ones
Also flushed heater core , how ?
The way heater cores are made on these KJs makes it hard just to flush water through and call it good

My 03 and 04s will run you out within 2-3 miles
The 05s is a bit off though , it gets hot but not nearly as hot as the other 2
 

JeepLibertyGuy

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Hi from Missouri....folks, I have a 2002 Limited 3.7. The heater is not real hot. I've flushed the core, installed a new radiator and hoses. Gets fairly warm setting still, but once moving down the road, it's temped at best.
Any info would be greatly appreciated.
Thanks


I’m experiencing the same issues and what I’ve narrowed mine down too because I’ve done the same steps as you; when you change from hot to cold with the temperature do you hear a buzzing sound? Usually heater issues can be

low antifreeze clogged hoses clogged heater core, blend door or the heater core itself.

from what I’ve learned it’s a very common issue. Unfortunately if it’s the heater core you would have to semi take apart the dashboard to move it out of the way.
 

JeepLibertyGuy

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I’m experiencing the same issues and what I’ve narrowed mine down too because I’ve done the same steps as you; when you change from hot to cold with the temperature do you hear a buzzing sound? Usually heater issues can be

low antifreeze clogged hoses clogged heater core, blend door or the heater core itself.

from what I’ve learned it’s a very common issue. Unfortunately if it’s the heater core you would have to semi take apart the dashboard to move it out of the way.


Oh yeah and thermostat, did you replace it? Does your engine overheat?
 

CopterDr

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Yep, new therm.....engine runs perfect temp....dead in the middle of the gauge. I've been watching to see if maybe the therm might not be closing all the way.....temp gauge stays dead on. Thanks for the get back too!!
 

CopterDr

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I’m experiencing the same issues and what I’ve narrowed mine down too because I’ve done the same steps as you; when you change from hot to cold with the temperature do you hear a buzzing sound? Usually heater issues can be

low antifreeze clogged hoses clogged heater core, blend door or the heater core itself.

from what I’ve learned it’s a very common issue. Unfortunately if it’s the heater core you would have to semi take apart the dashboard to move it out of the way.

Yeah, I've heard this now for sure.......don't relish taking the whole dash out....guess Jeep didn't put a big enough core in her. Thanks
 

CopterDr

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Yeah, I've heard this now for sure.......don't relish taking the whole dash out....guess Jeep didn't put a big enough core in her. Thanks
Yes Sir....I thought maybe the door actuator had failed...but it seems to divert the air like it's supposed to.
 

tommudd

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Yeah, I've heard this now for sure.......don't relish taking the whole dash out....guess Jeep didn't put a big enough core in her. Thanks
Heater core is big enough , so that is not the reason at all ,
 

tommudd

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Yep, new therm.....engine runs perfect temp....dead in the middle of the gauge. I've been watching to see if maybe the therm might not be closing all the way.....temp gauge stays dead on. Thanks for the get back too!!
BUT<>>>>>>>>>>>>>>>>>>was it a MOPAR one, makes a difference , guess you don't read all posts
 

CopterDr

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Did you also replace the thermostat
if not get a MOPAR works way better than those "zone ones
Also flushed heater core , how ?
The way heater cores are made on these KJs makes it hard just to flush water through and call it good

My 03 and 04s will run you out within 2-3 miles
The 05s is a bit off though , it gets hot but not nearly as hot as the other 2



OK...I'll get one from Mopar.....thanks
 

LibertyTC

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Yes please use HOAT or Zerex-05 coolant only W/ a Mopar thermostat.
Here is the diagram & part # below.
You must be registered for see images attach

Once the new thermostat is installed and the system is filled....
Once hot, You can also loosen the hex air bleed, to get a bit of coolant out/ remove air out of system as well.
You must be registered for see images attach
 

Billwill

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Yes Sir....I thought maybe the door actuator had failed...but it seems to divert the air like it's supposed to.

The "diverting of the air" ie. from Demister to footwells, side vents etc. is actually a seperate operation which is operated by vacuum from the intake manifold in the Gasser and from a seperate vacuum pump in the CRDs.

So there may still be an issue with the Blend Door which is seperate....driven by a Stepper Motor.

Follow the advice above as regards the Thermostat and the correct mixture of HOAT or Zenex antifreeze.;)
 
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