What's up with my heat?

[yukon06]

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

 

[OR VietVet]

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?

 

[Fless]

When did this start -- what work, if any, was done just prior to the issue? New radiator? Other parts?

 

[yukon06]

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]

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

 

[Fless]

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.

07 Tahoe engine hot ac turned off

You are on to something there, with the radiators. Struggled with the hot, AC off bs for a while. I made a number of cooling system improvements at the same time, so it took a while to figure it out. But I think I have it solved on my machine. Source of the problem: Aftermarket radiator...

www.tahoeyukonforum.com

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.

 

[yukon06]

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]

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.

 

[yukon06]

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?

 

[yukon06]

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….