timmwg

my 2009 max had the heater core replaced & bled the system, heat blows hot when driving, when i stop it blows cool air, when turned all the way up. doing the exact same thing as before. Anybody know what else could be causing this?? THANKS

Les7311

Pop the hood and check the coolant. Was it drained prior to surgery? Top it off.

While engine cold, and not running, open the radiator cap and squeeze the large top radiator hose for a few minutes. You could have air pockets in the system - will see bubbles coming out. Follow this YouTube link.....burping the radiator

https://youtu.be/cRPEqO06O58

Try that and update us.

timmwg

had the heater core replace.....damn heater still cold at idle. Damn, Damn, Damn!!!

Les7311

was the heater core the problem? Did they / you "burped" the system as shown in the youTube vid?

BronxSleeperMax187

Burp system...be happy

2000G6

has your engine ever overheated?

Bificus99

Also check hoses coming in and out of the cabin for the heater core. If they are both hot then its not the heater core, maybe a blend door.