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HVAC Fan Noise

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  • 7 months later...
On 4/6/2020 at 9:09 AM, DirtyAndy said:


At a certain fan rpm(one notch just below half) my fan will create a slight whistle. It’s by no means awful, but is noticeable. Just curious if anyone else has had something similar? Doesn’t seem to matter if it’s on defrost, front, etc.


I have a 2020 3.0 Duramax diesel.  Similar sound at same "certain rpm" fan speed, mainly slower.   Whistling noise started at 15,000.  I checked to make sure all vents are open.  Troubleshooted through all vent settings (defrost seemed to make it louder). Only setting that makes it go away is the recirculating mode.  Hate to keep it on recirc mode because it takes it off Auto mode.  


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On 3/13/2021 at 11:56 AM, Jonnynorway777 said:

There’s a 30$ Insulated pad you can buy from GM that will fix the fan noise issue

Part number is: 84487175

Description: lower insulator for passenger side (hush panel) 


You’re welcome


On 3/14/2021 at 4:03 PM, gemarsh said:

Came with my Denali. 



Thank you for pointing this out! Our '21 Silverado LT did not come with that panel so I just ordered one. I hope it comes with the mounting hardware, but it looks like they used three generic plastic "Christmas tree" push fasteners that I can probably get at the hardware store. We get some random squeak noises from the passenger side dash so I hope this helps.

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