2011 gmc terrain heater not blowing hot air

you have a air lock...Start the car with the radiator cap off. One of the easiest ways to bleed your car's radiator is to simply remove the radiator cap and then start your engine. Leave the vehicle running until it reaches its normal operating temperature. It may take between 15 or 20 minutes before your car generates enough heat to push out the air that has been trapped in your car's cooling system. You may find that you need to add additional coolant, as air pockets can artificially inflate coolant levels.
hope this helps

heater blows cold air idle chrysler 300 Questions & Answers ...

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Find solutions to your heater blows cold air idle chrysler 300 question. ... blow warmair for a few mins then back to luke warm. i replaced thermostat ... HEAT BLOWSCOLD AIR WHEN IDLING ONLY GETS HOT WHEN START DRIVING ... About 15 minutes after driving the diver side vents start blowing straight cold air but the ...

Heater only works when pressing the gas? - DoItYourself.com ...

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Nov 3, 2011 - When I press the gas, the air from the vents is nice and hot. .... So am Idriving a car with a ton of problems, or could the power steering ... Just anotherquestion, when warmed up does the engine temperature ... When the heater is on and I'm not pressing the gas pedal, luke warm air blows from the vents.

Heater blows cool air when stopped and warm air while ...

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RedditFeb 12, 2014 - Heater blows cool air when stopped and warm air while driving 2008 Kia Spectra (self. ... just fine but appears to blow cool air when I was stopped at a stoplight. ... My temp gauge would also be pegged high when at idle / low RPM. ...thermostat only blocks coolant going to the radiator, and the heater core, ...Missing: 300m ‎luke

Why is My Car AC Blowing Hot Air? - BlueDevil Products

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There are a number of possibilities.
First, its the level of coolant in the radiator full?
Low coolant level will cause this, because the heater is higher than the engine, so air can rise to the heater and form an air-lock.
Second, is the thermostat good?
A thermostat that is stuck open will not make heat for the heater.
Third, the control valve may be stuck or broken, not allowing the hot water to flow to the heater core.
Usually these are vacuum operated, and usually found under the hood.
God bless your efforts.

thermostat is sticking open

Check antifreeze level, if it's ok then it could be a problem with heater core

Probably a stuck open thermostat or the thermostat is the wrong temp range for your vehicle.

First check your coolant level if your coolant is good then it is probably your thermostat. If the thermostat is old it can be stuck shut.

ther are a couple of things that would cause this. im assuming that the blower is still working (blowing cold air) .if the blower is still working i would check the coolant level in the rad first. if the coolant level in the rad is good then i would check the thermostat. you can do this by getting the vehicle up to operating temp and checking the upper and lower rad hoses. if one hose is really hot and the other is cold or luke warm i would replace the thermostat. ( watch out for the belts when checking the hoses!)
if both hoses are the same temp the thermostat is probably good. from ther i would check the two coolant hoses that are going into the car (you should be able to see them on the passenger side of the engine compartment going through the firewall into the cab). same idea as the two rad hoses , feel the tempeture of the two hoses and if one is really hot and the other is cold or luke warm, then your heater core needs to be flushed out . any more questions just leave a message !

Check coolant level. Check for heat at the heater hose going from water pump to heater core at firewall. Check to see that cable is moving coolant control valve from the closed to open position. Low mileage so it shouldn't be plugged heater core.

check thermostat and coolant level