2008 Impala heat problems

It sounds like you have a leaking engine cylinder head gasket, the combustion gases are getting into the cooling system and causing an air pocket, this leads to overheating and other symptoms you mentioned.

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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You need to fix the coolant leak, then refill and bleed cooling system, then you will get heat and cure overheating problem too

It could be your heater core or check your over flow tank for the radiator to see if it is your antifreeze is up to the line marked on the side of tank and check the over flow hose, make sure the clamps are tight.

There can be all sorts of other DIY's from draining, flushing and refilling system, thermostat replacing and buying a new car.
Mine from City Peugeot was going to be a £2000 fix and they didn't even know what was wrong.It was just a hail Mary.
Other things that beat them was the rear light cluster not working - £400 fix, was just a loose fuse in the glove box.
The 26mpg when it should be 43, they just say is in the ok bracket, even though I reported it within 2 months of buying and it was sold as 43mpg.
Best advice - do not buy another Peugeot. I now cycle everywhere unless it is raining. I stay local and cant afford another car. Thats all fair I suppose.

water pump or heater core if not real hot when ur driving

check the heater hoses going from motor thru firewall to heater core / if they get warmer when motor is at 2000 rpms or higher then most likely problem is heater core stopped up / if the hoses dont change then thermostat could be stuck open ! good luck

It sounds like the coolant system is low.Possible coolant leak and /or headgaskets.

Have you checked your coolant level? Sounds like it MIGHT be low....

change your thermostat.