Heater blows hot air while car is moving but cold air while idling. The intake manifold was changed last spring, the thermostat has been changed 3 times and the temperature sending unit has been changed. We had the radiator cleaned out and changed the water pump. It was leaking antifreeze from somewhere and was running hot so we finally put stop leak in the radiator which stopped the antifreeze leak but it still runs a little hotter than it did before all of the above and now the heater problem.

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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Firstly, a thermostat that opens quicker will not give you better heat. Your heater core may be partially plugged causing a low flow issue. Another area to check would be the water pump impeller for corrosion or slipping on the shaft. Does the vehicle's cooling system operate well otherwise?

Are you sure you burped the air out of the cooling system after making those repairs?

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Usually it's a leaky thermostat allowing to much coolant to pass through it when it's closed.To check this, clamp off top rad hose completely(acting like a closed thermostat) If you have hot air from the heater now ,you do need a replacement thermostat.

No, because it blows cold air when it gets hot. There is air in the system or the coolant is low. Intake manifold gaskets are a very common problem on these engines and if left unattended to can cause even bigger problems such as head gaskets if the engine over heats too much. Check the coolant level and if it is low, look for leaks at the water pump, radiator and especially the intake manifold where it meets the head. Also, pull the oil dip stick an/or the oil cap to see if it looks milky. If it does, there is coolant getting into the oil.

Does your car overheat too?
If so, you could have a faulty thermostat, an air pocket in your cooling system or maybe even a leak somewhere. My truck's heat would only work while I was driving, then stopped working altogether while the engine started to overheat. I changed the thermostat, then the heat would blow hot/cold/hot/cold, I didn't realize you had to bleed the air out of the system after changing the thermostat. I did that and now the heater and engine run great.

ok there is a few things might be happening...first did you make sure when you put the intake gaskets in there was No ports plugged or covered...second is...are both heater hoses Cold or is one hot and other cold...if so you have a air lock in the heater core...if this is the problem you need to lossen off the cold one till antifrezze comes out.

make sure it has a thermostat

With the car warmed up,feel the heater hoses,are they both warm/hot near the firewall in the engine compartment?If they are both warm/hot,then the heater core should have circulation through it and it may be a "blend door" issue in the heater a/c assembly.If they are not warm/hot then the heater core could be dirty and plugged up and needs to be flushed.
If the above does not help,a drain and vacuum of the cooling system and vacuum refill will remove any trapped air.
Sometimes,clamping off the top rad hose and holding the engine rpm at 2000 rpm will force trapped air out of the heater core.(Watch temp gauge when trying this)
Lastly,a NEW thermostat doesn't mean its working correctly.

1 Inspect Cooling System Mix Coolant level low or flow is restricted. 2 Inspect Thermostat Thermostat stuck closed 3 Inspect Heater Control Valve Leaking or defective heater control valve. here something to help u

Here to help Shaun