why is my heater blowing cold?

[brownscampmj]

My blend door changes to allow the different temperature changes but it still blows cold air. Could my heater core be plugged and just need to be flushed? I'm not over heating or any problems of any sort except no heat

[jimoshel]

A good start would be to feel the heater hoses and see if hot water is reaching the heater core. With the engine warmed up and the heater controls on 'hot'

[Eagle]

Also check the coolant level. When the level gets down (and it doesn't have to be very much down), coolant doesn't get to the heater core.

[HOrnbrod]

Also check the coolant level. When the level gets down (and it doesn't have to be very much down), coolant doesn't get to the heater core.

 

Maybe, maybe not. It's not true with the HO open cooling system, but since the OP does not state WTH he is driving - :dunno:

 

People, please edit your signature to detail the year, model, and engine of what vehicle you are referring to.

 

EDIT:  Thanks OP.

[Blue88Comanche]

My blend door changes to allow the different temperature changes but it still blows cold air. Could my heater core be plugged and just need to be flushed? I'm not over heating or any problems of any sort except no heat

 

Check the heater core valve, it may be stuck or the vacuum line may have become disconnected.  The valve can be removed with some creativity, if you choose not to replace it. 

 

Have you verified the heater door cable is connected to the door arm under the passenger side dash?