Heater blowing cold air with coolant, fine with plain water

If both hoses are hot, the problem could be the inside...could be a blend door actuator

Not sure how much time you are talking about. The heat you get is from the water in the engine. The heater will not blow hot air till the engine coolant water heats up. The engine water flows through the heater coil under the dash air will blow across the heater coil and give you hot air coming out the vents. Engine has to heat up before you get hot air from you heater.

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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Sounds like ur ac pump is locking up its time for another one and also is your coolant level okay maybe ur heater core went out they dont give early signs of quiting they just go out

Check antifreeze,coolant,thermostat could be seized controls when engine is hot for heat

I like that you were knowledgeable to check both coolant lines tells me you are getting hot coolant through the heater core next thing to check will be the blend door on the inside of your vehicle. The blend door is a door that switches from cold air duct to heater duct depending on what you are using at the time. If it is stuck on the cold air duct you will not get any heat sometimes these doors are vacuum actuated and sometimes they are electrically actuated most the time you are able to see the movement of the motor from inside if you don't see any movement but you hear it move chances are it is the door blend I hope this helps.

Did you mean the only time it blows hot air is under acceleration?

First thing check the coolant level in the radiator. If coolant is low the first hing to stop working is the heat.

If the coolant level is fine but the coolant is muddy I woulds suspect a plugged heater core. You can try back flushing it by removing both heater hoses (engine cold) and then use a garden hose to flush clean water through the heater core. Do this on both pipes going into the heater core. Keep flushing until the water runs clear. Re attache the the hoses, remove the radiator cap, start the engine, let the engine come up to temp and top off the radiator with straight coolant (to comp for the water in the heater core). You may have to repeat this process several times over several days but you should be able to get it cleared enough to get sufficient heat without having to replace it.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Hi Jens,

Two things are happening.

The first is normal. Your heater gets its heat from the coolant ciculating in your engine. In order for it to work, the coolant needs time to heat up a bit. This is true of just about every vehicle.

When it gets cold again is the puzzler.

My advice is to check the coolant level in the radiator.

ONLY when the engine has cooled.

If the level is down, there can be times when there isn't enough water to cool the engine, fill the radiator and the heater core. The result is the heater blows cold air and the engine runs hotter than normal.

So check the coolant. Open the cap. Start the engine and top it off.

Then see if there is a change.

Best regards,
Mike

You have an air pocket in the cooling system. To bled it out you will have to park vehicle on an incline or jack up the front end untill the radiator cap is higher than the heater core. The remove radiator cap and run engine until warm then hold rpm to about 1200 rpm's and top off coolant level until you have no more bubbles.

The heater in your car depends upon a flow of hot coolant going through the heater core in order to get hot air into the car. If the heater core is partially plugged, it will restrict the flow. If you have a head gasket that is putting exhaust into the cooling system, it will eventually get into the heater core. When this happens there is no coolant in the heater core to make the air warm. If the water pump vanes have corroded away the result will be very poor coolant circulation causing the heater to not blow hot air. If your car is equipped with a heater control valve that is not functioning properly, the coolant flow will be restricted. One or a combination of these factors is likely the culprit in your case.
if the car is not overheating, the thermostat is working fine.... replace or flush the heater core multiple times to try and eliminate sediment build-up.