AC whistle sound?

WhiteLTZ14 · April 3, 2014

Hey guys! Im having issues with my AC... when im driving 50+ mph and have the AC recirculating button on... i here a whistle sound and when i turn off the recirculating button off the sound goes away. Does anyone know what it might be? Or have any of you had that issue before?. It's CC 2WD LTZ silverado if that helps.

Gun Designer · April 3, 2014

My 2011 Sierra has a motor noise that almost sounds like a chirpy whistle. Only does it when its in auto mode and kinda mid range speed.

8.1HD/ALLISON · April 3, 2014

If its only on recirculate I would check the recirculate door

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WhiteLTZ14 · April 3, 2014

My 2011 Sierra has a motor noise that almost sounds like a chirpy whistle. Only does it when its in auto mode and kinda mid range speed.

I messed with all the buttons and I narrow it down to when the air is recirculating. Im wondering if the gates are not closing all the way? It only does it when im going at 50+ mph if i go below speed i wont hear the whistle noise. My silverado is 2014.

8.1HD/ALLISON · April 3, 2014

2014 , take it to the dealer. Its under warranty.

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WhiteLTZ14 · April 4, 2014

Took it to the dealer and tech said they couldnt replicate the sound. Took the tech for a test drive i heard the whistle along with another guy that works at the dealer he heard it too but the tech said he couldnt. He said he can take the dash apart and look in there and see if anything is wrong but he recommended not too. They said they will call GM and see if they have any issues with that or what they recommend to do.

pm26 · April 6, 2014

There is a whole thread on recirculating door apparently not closing all the way and causing fumes and other road smells to enter the vehicle. It seems that "whistling" would be the sound of air outside moving past a partially closed recirculating door. Another great redesign by GM. They cannot leave what works alone.

WhiteLTZ14 · April 6, 2014

There is a whole thread on recirculating door apparently not closing all the way and causing fumes and other road smells to enter the vehicle. It seems that "whistling" would be the sound of air outside moving past a partially closed recirculating door. Another great redesign by GM. They cannot leave what works alone.

I found the thread you are talking about and im going back to my dealership and see if they can close it all the way instead of 90%. Hopefully that will fix it.

8.1HD/ALLISON · April 6, 2014

The recirculate door does not close all the way so that you always have a constant positive pressure of fresh outside air. Otherwise you would suffocate from lack of oxygen, in theory. I dont know that the trucks are that sealed, but thats why.

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bbond · August 9, 2016

any updates on this ? i have a cc 2wd ltz 2016 doing the same thing

Brian2015 · August 9, 2016

U sure you don't have a dash vent closed? Mine sounded like a jet engine, then I realized my kids closed off the passenger side vents.

EFLine · August 10, 2016

I have the same issue and cant figure it out. Will have to check this and see. Truck is in the dealership now getting work done and have a 2016 suburban as a loaner and have the same issue.

do you have the link to the thread referenced above?

ricker6869 · August 10, 2016

U sure you don't have a dash vent closed? Mine sounded like a jet engine, then I realized my kids closed off the passenger side vents.

I had this exact issue...I thought my filter was clogged...turned out to be a almost fully closed vent on pass side. Never crossed my mind until I went looking to change the vent filter....lol. Very noticeable whistle sound.