2011 sho 8k miles the heater heats great while driving till ya stop for a stop light,Then it starts blowing cold air when the light goes green by the time your through the intersection it has hot heat again..Any body else experience this problem.And yes the coolant is full and experiencing no other problems.
No heat at idle
- Thread starter scooter8
- Start date
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Ishodu
SHO Member
Sounds like there may be air in the cooling system.
hawkeye18
Sorta cares
On a car with 8,000 miles on it? I would be surprised. Unless it's done it since new. Anything's possible from the factory. It should've burped itself by now, though.
I know that on my old '94, when I'd slam on the brakes the blend door's new-found inertial mass would overcome its motor's ability to hold its position and the heater would blow cold air for a few seconds. I found this to be handy, as panic-braking was usually accompanied by swearing and profuse sweating.
What may have happened is that your blend door actuator motor is not working right, and is not holding the door's position. When you brake, it swings forward to cool, and when you accelerate again it swings back to cool.
Try putting the A/C in cool mode (MAX A/C works well) and flooring it, then see if it blows hot air. If it doesn't, something else is wrong. If it does, the blend door actuator needs replacing. This is where you rejoice in warranties.
I know that on my old '94, when I'd slam on the brakes the blend door's new-found inertial mass would overcome its motor's ability to hold its position and the heater would blow cold air for a few seconds. I found this to be handy, as panic-braking was usually accompanied by swearing and profuse sweating.
What may have happened is that your blend door actuator motor is not working right, and is not holding the door's position. When you brake, it swings forward to cool, and when you accelerate again it swings back to cool.
Try putting the A/C in cool mode (MAX A/C works well) and flooring it, then see if it blows hot air. If it doesn't, something else is wrong. If it does, the blend door actuator needs replacing. This is where you rejoice in warranties.
kageryu
New Member
I've got gurgling in my heater core when accelerating away from stoplights after going down two floors of parking garage ramps, so it might not be impossible 
(Though, dunno if that is because they did something halfassed with my fan replacement?)
(Though, dunno if that is because they did something halfassed with my fan replacement?)
hawkeye18
Sorta cares
Oh... then it sounds like air in your cooling system.
This happened with my 2010 in January. It had 43,000 miles at the time. The tech who took care of my '92 SHO for many years, and now takes care of the 2010 said he recently fixed this problem on a Fusion by back flushing the heater core. He back flushed the heater core on the SHO and the heat has blown hot at idle since. Sorry for being late with the response, but I haven't checked this site in a while.
SHOrod
Torrie Tuned
I'm running in to this same issue on my wife's MKT. I notice it on the passenger side. She claims the driver's side doesn't do it. I haven't checked/bled the system yet, but I also need to check the blend door I guess since it's still under warranty. Thanks for the idea!
-Rod
-Rod
esfoad
Esfoad
A difference on the two sides sounds like the blend door. No, or less, heat sounds like the system needs to be bled.
Night hawk
Member
Blend door def went through the same recently.
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