Cool air at idle with heater on.

[396375]

My 2010 MKS has a problem with cool air coming in when the heater is on at idle.Once the car starts driving the heat comes in and everything is fine.I have replaced the blend door module behind the glove box.I'm thinking there is another one that is the problem.
Thanks

 

[SHOdded]

Usually this is due to low coolant or perhaps an air pocket in the cooling system.  Make sure the coolant is at or slightly above the COLD FULL mark when engine is off/at ambient.

 

[ZSHO]

X2 -  probably have an air pocket in the system.
Stat original  ? Z

 

[Brucelinc]

Very common issue.    As Shodded said, add coolant to a bit ABOVE the cold full line when the engine is cold.

 

[Blackhawk]

This, and keep doing it every couple days until it stops lowering. 

Very common issue.    As Shodded said, add coolant to a bit ABOVE the cold full line when the engine is cold.

 

[396375]

Thanks guys.I'll give it a try.

 

[396375]

3 Quarts  later I have continuous heat.Thanks to all.

 

[SHOdded]

Awesome!  Enjoy.