2006 heat issue

[honey17578]

I have a 06 Tahoe and it has a couple issues but the one that I need help with is the heat. After the vehicle is warm it will blow hot air only while driving. As soon as I stop for a light or wait in the car for my wife to get something in the store it blows cold air. It wouldn't be a big deal except I have a 3 and 1 year olds in the car with me. Any ideas as to why it might be doing that?

 

[MO Viet Vet]

Did you check the coolant level? If is low then it may not get hot coolant up to the heater core. When it does it do you hear anything different in the dash?

 

[honey17578]

I checked the coolant level and it was good and I didn't here anything in the dash. The coolant temps are normal and that's why this is confusing me.

 

[MO Viet Vet]

If the coolant level is full and if the blend door actuator is not going funky at idle then need to check elsewhere. First, need to be sure the signal for actuator is not being lost and allowing door to close but not likely. I would want to see if the water pump is pushing coolant around enough. The impeller may be failing and therefore the coolant is only being pushed enough at higher speeds. You may also have a partially clogged heater core. There was another rig on here about 3-4 days ago with the same type of problem and he disconnected the heater hoses and blew out the heater core with water pressure and a glob came out and then he had the heat like he wanted. Did you google your symptom?

 

[honey17578]

I didn't I just come on here when I have something that has me stumped.

 

[MO Viet Vet]

No problem with that. I would google it and then you may have someone that has the exact same problem and what they did to fix it. The system typically does not get as hot at idle so you may have a thermostat going bad. You may also have a vacuum leak causing loss of vacuum to the controls.

 

[remauto1187]

Assuming it isnt a problem with blend doors (automatic climate control) then this is a classic symptom of a clogged up heater core and has been for many many decades.

Quick and dirty tattle is to hit the inlet of the heater core with a IR thermoter and then check the outlet. If there is a substantial temp difference then your heater core is plugged up. The outlet will be alot lower than the inlet because no coolant or very little is flowing out of the heater core. Radiator shops charge around $30 to flush it with a solution and high pressure.

The cause is usually a rotted out radiator floating debris to the heater core and/or some knucklehead mixing pink and green antifreeze in the coolant system which ends up with the looks as if 30 people puked in your coolant system....chunks and all!