Sorry to start another no heat discussion... Jeep is 2004 4.0. I have been battling this since I got the jeep. Jeep has a 195-degree thermostat, new water pump, new rad, and heater core... did each one at a time over the summer. I have hot coolant that goes to and from the heater lines both about the same temp (flushed it anyways today to see, and nothing). The jeep stays just under halfway on the temp gauge when driving around. No clue why I don't even have decent heat the coolant level is good and have no leaks. ( last yr could partially defrost the window and this year not so much until it is at full operating temp but is still cool to the touch) Took the blend door actuator out and made sure it goes fully each way and that is all good. The only thing with that "system" is the knob on the far right (vent selector) needs to be turned with pliers as it breaks the knobs from being so tight could that be the possible issue? or can the heater core just be bad, had a shop do that in the summer. Any help is appreciated, thanks!
No heat
- Thread starter Morks
- Start date
I’m gonna go ahead and guess that you have an issue with the vent not opening to let heat into the vehicle. Turning the vent selector with pliers is not normal. If you had a shop do the heater core than that could be related to the problem. Was the knob stiff before the work was done? If all the air is out of the system you should have heat.
How would I go about checking if the vent is open, do I have to take the dash apart, I'd assume so? The knob was stiff before the shop did it. Air is definitely all out of the system... Do you ever fish for those monster Maine brookies? Looks sweet out there!
When you select different modes on the HVAC controller can you tell it’s changing for example from floor to defrost or is it blowing out all of them the same?
yeah, they all change like they should which is why I can't see why it would cause the issue.
Yes I fish for those brookies a few times a year! I’m not sure how to tell you if the vent is opening as I’m not sure what the inside of the heater matrix looks like. You could probably find a diagram on the forum some where. I know if you pull the glove box out you can see quite a bit of what’s going on.
I would say the heat control is your issue. It directly controls the blend door and if you are having to turn it with pliers it’s probably the culprit.
The heater knob isn't the issue just the vent selector, when the climate knob is turned the blend door rotates fully and the air is noticeably "warmer" than the cold...
Confused and you say the air is noticeably warmer yet you say you have no heat. So if the vent control is working and the heat control is working then how are you not getting heat?
I shoulda phrased it better, it goes from cold to less cold. If I'm fogging up on a cold day once my engine is fully hot then I can just barely get rid of it. I honestly have no clue cause everything has been gone over, has to be something simple that I'm just missing
How was the heat prior to changing the heater core? There have been numerous threads regarding poor heat performance with aftermarket heater cores.
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Not sure bought the jeep in the summer and knew it leaked so got it replaced, I don't remember it being warm only smelling coolant.
A lot of the aftermarket heater cores have plastic flow restictors that severely limit coolant flow as opposed to the o.e. style.
https://wranglertjforum.com/threads/very-little-heat-from-new-heater-core.31288/
https://wranglertjforum.com/threads/2004-lj-with-luke-warm-heat.46947/
https://wranglertjforum.com/threads/very-little-heat-from-new-heater-core.31288/
https://wranglertjforum.com/threads/2004-lj-with-luke-warm-heat.46947/
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That's what I am kind of thinking... in the LJ post, jerry refers to a "flapper" that may not be opening all the way. How can I check that? or is that something where I'd have to rip the dash apart to figure out.
I believe what @Jerry Bransford is refering to is your blend door may be stuck. Some people also refer to is as the temp door.
You can remove the actuator and move to door open/closed with a pair of needle nose plyers to check it.
Ah okay, yeah mines all good there. Not sure where to go with this other than swap the core if the shop put in a faulty one. I called them the next day saying I had no heat, they said clogged lines and they would have to charge more for diagnosing. Wasn't impressed
Having to turn the knob with pliers or hard enough to break the knob isn't normal.
I had a similar issue, and it turned out to be the selector knob.
I found it by mapping out the positon of each of the damper actuators vs the position of the knob. My dampers were opening and closing, just not in the correct order based on the knob selection. Installed a new one, and that fixed the problem.
I had a similar issue, and it turned out to be the selector knob.
I found it by mapping out the positon of each of the damper actuators vs the position of the knob. My dampers were opening and closing, just not in the correct order based on the knob selection. Installed a new one, and that fixed the problem.
I would get an infrared thermometer and check the temp of both heater hoses at the core.
So would that be the little motor-type thing (part 5013833AA)? Mine however open based on selection... Definitely going to switch it out soon.