What's up with my heat?

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yukon06

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Takes long to warm up and even then isnt that hot...maybe lukewarm....2006 yukon
 

OR VietVet

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The first thing that comes to mind is a failing thermostat. What does the temp gauge show after complete engine warm up? Grab the heater hoses at the firewall and check to see if they are approximately the same temp feeling. How about the hoses off the tees?
 
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yukon06

yukon06

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Just got the truck a few weeks ago so not sure when it started....no work done by me yet except replace some led lights....looking at list of things replaced
march 2021 - new radiator, thermostat, crossover tube
 

OR VietVet

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Back to basics then. Did you check the coolant level and for leaks? Does it say what brand parts were used in March?
 

Fless

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If an aftermarket radiator it may be missing the restriction in the return line that goes to the surge tank. The link below has a few suggestions.


I'd probably verify the thermostat temp, too, to be sure it's the correct one. But you can do a quick test about the restriction by clamping down the return line to the surge tank *somewhat* with a clamp of some sort and monitoring the engine temp while you do it. If that works, all you need is a more permanent solution. You'd want to be careful that it's not too permanent in case you ever go back to an OE radiator, or a radiator that has the integrated restriction.
 
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yukon06

yukon06

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so a little info im looking now....coolant temp sensor ts10076 35k miles ago.
radiotar 3653 crs 21k miles ago
thermostat and seal 131-156 and 131-169, crossover tube 626-543 installed 20k miles ago

i will check the other things in the am
thanks
 

Bill Barnes

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Had the same problem with my 2005 Yukon XL. Turned out to be the drivers side Blend door activator. Fairly easy fix, but make sure you get the correct part, which is based on your VIN. There were changes based on your date of manufacture. You Tube has detailed videos on haw to replace the activator; it HAS to be indexed correctly.
 
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yukon06

yukon06

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So I checked everything finally....
engine gets to temp as it should.
Blower works as it should.
the hoses going through firewall - on is very hot the other is even more than very hot.

All of that says the water pump and thermostat are fine, correct? With that in mind do I still need to try and restrict the little hose from radiator to reservoir? Im thinking no but I defer to you guys.

As for the blend door actuator...just want to be clear the issue is the same temperature or lack of warm temperature from everywhere....its not an issue of cold on one side hot on the other nor an issue of switching back and forth between hot and cold the issue is just barely lukewarm air from all vents....

Could still be blend door actuator?
If so, I think theres more than one or no, and if there is how do I know which one to replace?
I dont have the funds currently to be trial and error with parts but the cold weather is here and I need heat lol

Thanks

EDIT - just watched a video...there's one actuator and its under glovebox?
Is that my next move to replace or is there any more tests I can do?
 
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yukon06

yukon06

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Update
I have heat.
Yesterday i did the recalibration twice and teated and still no heat.
Today i got in and driving and realized hey its getting warm in here lol
Heat seems lile its working….
 

live2pull

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So I checked everything finally....
engine gets to temp as it should.
Blower works as it should.
the hoses going through firewall - on is very hot the other is even more than very hot.

All of that says the water pump and thermostat are fine, correct? With that in mind do I still need to try and restrict the little hose from radiator to reservoir? Im thinking no but I defer to you guys.

As for the blend door actuator...just want to be clear the issue is the same temperature or lack of warm temperature from everywhere....its not an issue of cold on one side hot on the other nor an issue of switching back and forth between hot and cold the issue is just barely lukewarm air from all vents....

Could still be blend door actuator?
If so, I think theres more than one or no, and if there is how do I know which one to replace?
I dont have the funds currently to be trial and error with parts but the cold weather is here and I need heat lol

Thanks

EDIT - just watched a video...there's one actuator and its under glovebox?
Is that my next move to replace or is there any more tests I can do?
If memory serves, there are 3 actuators for the front . 2 for temp (passenger/driver), and one for vent position. the one under the glove box is for driver temp, there might be another one under there, but it has been a while.
 
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yukon06

yukon06

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so i do not really have heat...its lukewarm at best and in this weather useless.....i started another thread i should have posted here though....
how do i know which correct actuator to order....
part numbers anyone? I see several
 

live2pull

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so i do not really have heat...its lukewarm at best and in this weather useless.....i started another thread i should have posted here though....
how do i know which correct actuator to order....
part numbers anyone? I see several
You will need to compare your RPO codes in the glove box to the actuator you need. There are at least 2 different climate controls in this generation and actuators for each (I assume).
 
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yukon06

yukon06

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ive googled how to choose the correct one and im not getting much info....heres my rpo codes how do you tell which model number i need to order
 

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B-train

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I was noodling on this and you mentioned that the hoses going into and out of the cabin were HOT and HOTTER. I'm wondering if you have a gunked up heater core. It was a notorious problem on some early dexcool systems........s-10 blazer and Jimmy come to mind. I remember at the dealership guys running a flush through them to clean out the shlt.

If you have a temp gun, see what your delta is with the blower on low, then on high. If you don't see much of a change, it's possible something was messed up already when the previous owner did all that work. Or something went downstream and is restricting the flow. Just a thought.
 
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yukon06

yukon06

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Ok so for the hoses in a different thread i started accidentally someone asked if one hose was hot and the other one a little less hot and that’s exactly how mine are I think thats how they’re supposed to be?

I bought truck a couple months ago without the rear working because the lines rotted out and they were capped off which i think is common but now i think is that just a/c or heat too?
 

B-train

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Both run back there. You'll know if you look under the hood. You can delete the rear due to rot by installing pickup truck A/C components. The rear delete is easy as well for the heat.

Yes, there should be a temp diffential between supply and return. If one is noticeably cooler, then it's working correctly.
 
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yukon06

yukon06

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so to update this thread also....

First, whoever designed the way the actuator mounts and also the plastic covering should be shot, then shot again.....these 'engineers' should be made to work on a vehicle and see how much fun it is to get those 2 bolts out....

I do have heat now....this is what I used and if it gets me through the winter im ok with that


Follow up question......im not used to a vehicle taking so long to warm up before I start getting heat, it needs to be at full operating temp before it gets warm, it also seems like it works better if im giving it gas rather than idling at a light or somewhere....is all that normal for a 2006?
 

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