Over the summer I picked up a 2013 Impala LTZ.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
I don't think the heater is quite up to par and may have some air in they system.<o></o>
What supports my theory when I make left hand turns I get a blast of hot air<o></o>
Is there an air bleed on the heater core?<o></o>

 

For all vents?

Do you have an actuator problem? The AC is fine?

Frank3 might have a better idea. This is definitely a strange sounding problem.

 

Everything seems to be working correctly <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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What I see is I can cruise down the Interstate with everything set comfortably. <o></o>
With ambient temp in the single digits the car temp adjustment will be near highest position (what happens when it gets cold outside) <o></o>
Next when I get into town or make a sharp left hand turn I get a blast of hotter air from the heater.<o></o>
To me it seems like the turn causes a slug of hot coolant to the heater core <o></o>

 

I had the dual climate control set up recently.. cold my side, hold passenger side.

I made a left turn, and I felt the hot the passenger side.

You should get a temp gauge for automotive purposes and stick them in your all your vents and note the hot temp and see if they are all the same.

 

is it in auto mode when it does this or manual?