No Heat - Confused - JeepForum.com
 
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post #1 of 7 Old 11-23-2019, 02:15 PM Thread Starter
mbrando1994
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2008 KK Liberty 
 
Join Date: May 2018
Posts: 5
No Heat - Confused

So I have a 2008 Liberty that has been without heat for over a year now. I took it to be diagnosed by a shop because after checking all the usual things I've come up short. Both lines running to heater core are hot, one slightly less hot. They are running at around 105-115 at the firewall. The actuator motor is turning when adjusting the temp dial. So the shop said it was a bad radiator cap, a bad coolant temp sensor, and a bad thermostat. I replaced all and swapped out the coolant with the pink Mopar HOAT stuff. Topped everything off and got all the air out of the system I could in over an hour of letting it run and squeezing the lines.

Before I had little to no heat at all. Now It gets sort of hot but then drops off and goes cold after a bit and cycles like that. It never gets really hot like you'd expect on the highest setting. Also, when I switch to defroster, even if it's currently blowing hot, it goes completely cold and stays there on defroster.

I am at a complete loss, could there just be more air in the system?

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post #2 of 7 Old 11-23-2019, 02:55 PM
pshivers
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2008 KK Liberty 
 
Join Date: Sep 2012
Location: Westerville
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Just curious if you ran the jeep with the rad cap off while bleeding the coolant system. Suppose to run until cooling fan turns on, then turn off the jeep and let it cool down. No squeezing of the lines are necessary. I did this 2 or 3 times for my piece of mind when I changed the radiator and water pump.

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post #3 of 7 Old 11-23-2019, 03:07 PM Thread Starter
mbrando1994
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I ran it with the cap off the entire time, I'm assuming the only danger was the coolant that ended up splashing out once it got too hot. I did this a few times though until the fan turned on and still nothing. It's very inconsistent. One time it's hot other times it's cold.
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post #4 of 7 Old 11-23-2019, 03:08 PM
pshivers
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Did you ever back flush the heater core? Seems like you have a trickle through the core.

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post #5 of 7 Old 11-23-2019, 03:17 PM Thread Starter
mbrando1994
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No, regretfully I did not back flush the heater core
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post #6 of 7 Old 11-24-2019, 06:51 AM
Ex-Calif
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2012 KK Liberty 
 
Join Date: Apr 2015
Location: Cincinnati
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Take a look at this video that might give you a clue to what you are dealing with. The way I understand it there are two doors - directional door and blend door. If the heat is good sometimes and not others and the heater hoses are hot I would suspect the blend door, blend door logic or blend door actuator.

Just because the actuator is moving may not mean the door is moving...

Another possibility is I have found the Jeep has pretty dodgy electrical systems. Sometimes I switch directional positions and nothing happens for like 10-30 seconds. Rarely I change positions and it never changes but I noticed that after shutting off and restarting the car it does - weird and leads me to electrical logic.

I don't know what's in the circuitry but there has to be some sort of controller for the door position as the heat know simply adjusts the blend door from full cold to full hot.

If I were to troubleshoot mine I might pull the lower dash valance (as shown in the video) and drive it around like that until the fault happened then I would check and see if the door moved "on its own." That would lead me squarely to an electric/controller issue.


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Last edited by Ex-Calif; 11-24-2019 at 06:52 AM. Reason: Forgot link
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post #7 of 7 Old 12-05-2019, 10:52 PM
Steve.A
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Thanks for the video Ex-Calif. I could hear my actuators moving, but was getting no heat on my 2011 KK. I pulled the covers below the drivers side dash off and found that the bottom actuator gear had pulled out of the blend door. The actuator was moving, but not moving the door. The entire plastic mount for the actuator motors and gears was twisted and slightly cracked at about the mid-point. It appeared as if the lower motor was turning one of the gears behind the mounting plate and something bound up and the motor kept torqueing away and bent/broke the mounting plate and pulled the gear off of the blend door when it twisted. I took it all apart and plastic welded and reinforced the mounting plate and put it all back together and it is now working like it should. The guy in the video alludes to getting the gears all lined up and putting it back together to be a challenge. It was. I think that if I have to do that again I'll pull the driver's seat to get some more room to work. Once the mounting plate is removed, the two black gears and 3 white ones just sort of fall out. Figuring out how they fit back together is a challenge. The gears have sort of a square cog on some of them, intermingled with the regular cogs and other gears appeared to be missing a tooth in spots. I finally realized that these were made that way to mesh the square cog with the tooth gap on the paring gears as an index of where they needed to go back together. Otherwise everything just won't fit back together.
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