No heat/Luke warm

TheCanadian

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So this has been on on going issue I've been trying to tackle.

Just some background.

- Heater core has been flushed and they said there is no blockage.
- They deem the thermostat doesn't have to be changed as it gets to operation temperature.
- I've been over heating for a bit found out that the rad fan hasn't been working. No clue how long but that has been replaced.
- I've done a rad flush as well with all new coolant as well.
- The air distribution box only blows out the defrost.

Anyone have any thoughts?
 

duderz7

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I've heard of water pump blades spinning on the shaft internally without leaking or showing wear externally, maybe it's not circulating the coolant the way it should. Or perhaps thermostat stuck open, therefore not reaching temp whem cold out...just spit balling here.
 

TheCanadian

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I've heard of water pump blades spinning on the shaft internally without leaking or showing wear externally, maybe it's not circulating the coolant the way it should. Or perhaps thermostat stuck open, therefore not reaching temp whem cold out...just spit balling here.
It is reaching operation temperature when it's cold out.

As for the water pump maybe I'll look into seeing if there's anything wrong with it.
I do have a thermostat on hand so I might go ahead and replace it.

Just wanted to see if anyone else had any ideas as the shop seems to be blaming it on the air distribution box not working properly.
 

duderz7

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So thermostat probably fine. I don't know how to check for proper circulation. Perhaps blend door not operating. Check hose temps at radiator and heater core after warmed up maybe?
 

TheCanadian

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So thermostat probably fine. I don't know how to check for proper circulation. Perhaps blend door not operating. Check hose temps at radiator and heater core after warmed up maybe?
The hoses going to the heater core are both hot. As for no/barely any heat in the cab I'm not to sure.
 

duderz7

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If both hoses arw hot i would suspect your blend door between hot and cold not working.
 

sota

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you can visibly see the actuators from the driver's footwell, as well as move them by hand. if they aren't moving, or you can't move them yourself, something could be wrong there.
our vent controls are vacuum operated, so make sure there isn't a break near the brake booster.

ETA: my saga starts here.
 
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TheCanadian

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If both hoses arw hot i would suspect your blend door between hot and cold not working.
you can visibly see the actuators from the driver's footwell, as well as move them by hand. if they aren't moving, or you can't move them yourself, something could be wrong there.
our vent controls are vacuum operated, so make sure there isn't a break near the brake booster.

ETA: my saga starts here.


I'll take a look at the actuators and see if they are moving. I believe the hot and cold one might possibly not be moving very well as when you change from hot to cold or the other way around it makes some popping sounds as like it's getting stuck on something possibly.
 

DadOSix

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you can visibly see the actuators from the driver's footwell, as well as move them by hand. if they aren't moving, or you can't move them yourself, something could be wrong there.
our vent controls are vacuum operated, so make sure there isn't a break near the brake booster.

ETA: my saga starts here.
That is a great tip Sota!

I've got my 04 coming home saturday with a report of weak heat and weak ac. Almost convinced it is the blend door setup with out looking at it first.
 

mjeep08

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So this has been on on going issue I've been trying to tackle.

Just some background.

- Heater core has been flushed and they said there is no blockage.
- They deem the thermostat doesn't have to be changed as it gets to operation temperature.
- I've been over heating for a bit found out that the rad fan hasn't been working. No clue how long but that has been replaced.
- I've done a rad flush as well with all new coolant as well.
- The air distribution box only blows out the defrost.

Anyone have any thoughts?
I have an 08 and the Blender door motor is your problem. I have replaced mine twice. Easy and only $20. The popping sound you here is the gears slipping. You need a Dorman 604-037 Air Door Actuator.
 

Elly

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So this has been on on going issue I've been trying to tackle.

Just some background.

- Heater core has been flushed and they said there is no blockage.
- They deem the thermostat doesn't have to be changed as it gets to operation temperature.
- I've been over heating for a bit found out that the rad fan hasn't been working. No clue how long but that has been replaced.
- I've done a rad flush as well with all new coolant as well.
- The air distribution box only blows out the defrost.

Anyone have any thoughts?
I had the same problem, turned out to be the clutch fan was broken.
 

24kkarat

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I'll take a look at the actuators and see if they are moving. I believe the hot and cold one might possibly not be moving very well as when you change from hot to cold or the other way around it makes some popping sounds as like it's getting stuck on something possibly.
I had this problem in my kk. If the popping sound happens when you try to change the temperature or defroster, then one of the actuators may have broken teeth or it is struggling to turn a flap in the the air distribution box. There is a problem with these jeeps in that the adhesive around the felt of the blend doors get messed up and adhesive sticks the flap in a position. It is often misdiagnosed. I my case I had to take the dash apart and replace that box. It's a lot of work, but that is the problem. If I can find my old posts I will point it back here. You can do it yourself if you are handy and determined. There are a couple of two part videos showing how and the problem. The way these work is you have full heat going into the box all the time and the flap diverts air in there or not for heat. So if air doesn't go the right way, then poor control or poor heat. You have already addressed the other obvious issues.
 

Sipafz

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I'll take a look at the actuators and see if they are moving. I believe the hot and cold one might possibly not be moving very well as when you change from hot to cold or the other way around it makes some popping sounds as like it's getting stuck on something possibly.
The popping noise is probably the plastic gear teeth jumping as the actuator cycles. In my case the blend door got stuck and the plastic gear teeth got messed up on the end of the blend door. If this is the case the entire air distribution housing will need to be replaced. Here’s a link to a video demonstrating the process to replace it:

DIY Heater Core Replacement - 2011 Jeep Liberty KK
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TheCanadian

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I'm going to try replacing the actuators since they are easy to get to. If it comes down to it I guess I'll have to take the dash apart which I'm not looking forward to....
 

sota

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That is a great tip Sota!

I've got my 04 coming home saturday with a report of weak heat and weak ac. Almost convinced it is the blend door setup with out looking at it first.
if it blows hot like a ***** ape after sitting overnight, then heat output drops off to a strangled straw, pull the clutch electrical connector off the A/C compressor, and see if the situation resolves itself over the next hour or so. worst case, let it sit for a couple hours, preferrably in a garage or at least well above freezing temperatures, then test again.
 

sota

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I'm going to try replacing the actuators since they are easy to get to. If it comes down to it I guess I'll have to take the dash apart which I'm not looking forward to....
see my above.
 

DadOSix

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if it blows hot like a ***** ape after sitting overnight, then heat output drops off to a strangled straw, pull the clutch electrical connector off the A/C compressor, and see if the situation resolves itself over the next hour or so. worst case, let it sit for a couple hours, preferrably in a garage or at least well above freezing temperatures, then test again.
Are you thinking the a/c is engaged?
 

Johnny O

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If the KK is a micro pneumatic/ vacuum control system like the KJ:

My suggestion: pull the HVAC control panel from the dash. Carefully disconnect everything. The micro pneumatics in the center are the most difficult, so be gentle.

Get a bottle of rubbing alcohol , keyboard cleaner, silicone grease/dielectric grease and some cotton swabs. Inspect the small pneumatic connections (tubes) on the white plastic of the panel. Make sure they are clean and clear and then swab the contact point around them with a very thin layer of the grease.
Now clean all the electrical contacts on each side of the circuit with alcohol and give a thin coat of dielectric grease.
Next, inspect and clean the infamous christler micro pneumatic connections. Pun intended. This is the rubbery round amber colored connector in the center of the panel that controls the vents. Carefully clean the connector with the alcohol and then b.low it fully clean with the keyboard cleaner at a 90 degree angle to the holes. Do not bl.ow any thing into them, only across them.

Inspect the micro pneumatic tubes for damage. If good, then gently l.ube the contact surfaces with the clear grease. Be extremely careful to not block or get grease in the microtubes.

Re install the panel and let it sit undisturbed overnight to allow the dried out polymers to soften back up and seal properly. Then cross your fingers and hope all that work paid off.

I had this issue in my KJ and a coworker’s kj. The amber rubber pneumatic seal gets old and har.d causing leaks. By cleaning and l.ubing, a proper seal was restored so that vents properly opened and closed to allow better airflow.

Id like to meet the engineers behind this system in a dark alley. It is silly.
 
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Sipafz

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If the KK is a micro pneumatic/ vacuum control system like the KJ:

My suggestion: pull the HVAC control panel from the dash. Carefully disconnect everything. The micro pneumatics in the center are the most difficult, so be gentle.

Get a bottle of rubbing alcohol , keyboard cleaner, silicone grease/dielectric grease and some cotton swabs. Inspect the small pneumatic connections (tubes) on the white plastic of the panel. Make sure they are clean and clear and then swab the contact point around them with a very thin layer of the grease.
Now clean all the electrical contacts on each side of the circuit with alcohol and give a thin coat of dielectric grease.
Next, inspect and clean the infamous christler micro pneumatic connections. Pun intended. This is the rubbery round amber colored connector in the center of the panel that controls the vents. Carefully clean the connector with the alcohol and then b.low it fully clean with the keyboard cleaner at a 90 degree angle to the holes. Do not bl.ow any thing into them, only across them.

Inspect the micro pneumatic tubes for damage. If good, then gently l.ube the contact surfaces with the clear grease. Be extremely careful to not block or get grease in the microtubes.

Re install the panel and let it sit undisturbed overnight to allow the dried out polymers to soften back up and seal properly. Then cross your fingers and hope all that work paid off.

I had this issue in my KJ and a coworker’s kj. The amber rubber pneumatic seal gets old and har.d causing leaks. By cleaning and l.ubing, a proper seal was restored so that vents properly opened and closed to allow better airflow.

Id like to meet the engineers behind this system in a dark alley. It is silly.
KK is full electric.
 
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