I hate to mention this, as once you hear it, you can’t unhear it.

I read some posts about people have whistling when their HVAC was on high setting or if recirc was on. Also, read about the high pressure (which I believe stems from the whistling issue)in the cabin and the TSB to add some additional holes to help air exit the cabin to keep the pressure neutral.

This is not the issue I am having...with the radio off, there is a hum anytime the HVAC is turned on. It doesn’t matter what speed it is set to, the hum is the same volume and the same pitch.

I typically have music turned up and don’t notice, but sitting in the drive-thru at the bank, I heard the hum and now cant unhear it.

I tried turning on/off A/C, recirc, different fan speeds, and directing the air to different ducts, but the sound is present anytime the blower is on. I typically have the fan setting at 1. However, at speed 1 it is the worst, as the sound of the air through the vents isn’t loud enough to mask the sound.

I am pretty OCD, but never noticed this in my 08’ G500, nor any other car I can remember.

Anyone else notice this? Best way to drive yourself crazy is to sit in the car with no audio playing and switch from fan speed 0 to 1.....

 

Guns n Roses - best remedy for squeaks, rattles, chatters, hums, thumps, clacks, ringing, grinding, whistles and whirs across the spectrum of human hearing and beyond (lol).

 

There’s a setting in your HVAC menu that allows you to change to I believe it’s called “Diffuse”. That made a difference for me. I too noticed the whistling and that helped.

 

Dang, I even have it on defuse...I hadn’t even tried to change it to “focused” or the other mode when I was playing around with the settings.

I am glad I am not alone in hearing it...sounds like the resolution is to keep the tunes pumping.

 

Mine is basically silent, and has none of the problems that many here are reporting...they must have liked Desert Silver so they made sure everything was done properly!

 

I don’t have any noise with mine either...

 

You should "demo" the Hum with your Dealer .. haven't had any reports of "Hum"/Vibration

 

Maybe this help

From begining I dont have whistle in my car when ac on, but I been on detailing center where guys take off door panels and after that I collect car I start to hear whistle even on 1 fan speed. So I came back to detailing center where guy on my eyes take off door panel (previously I find that mostly whistle come from rear left door, somewhere from center of door like a window) so he take off panel, preasure to all sealants, then make same with drivers door and after that whistle is gone

 

I contacted my sales person and he relayed the following message to me:

“I spoke with our service manager. He had one g550 with a similar issue. He thinks it could be a seal around the air filter. He said to check the fire wall under the hood and see if anything looks like it’s out of place. Like a plastic clip or something. But is most likely a seal.”

This dealership gets one 550 allocation (zero G63) per year. So it sounds like this may not be an uncommon issue.

I glanced under the hood when I got home from work and inspected, what I believe to be the cabin air filter. (Passenger side near fire wall).

It looked like it was fastened by 2 plastic clips. It was -10 outside today (car sat outside all day) so I figured it was best not to be prying on plastic clips....as I know what would happen...

Anyway, I am guessing the air filters are located under the plastic engine bay cover...?

I didn’t notice any seals around the firewall, other than the area around the cabin air filter....but will dig into this more and keep this updated.

(Closest dealership is 6hours away, otherwise I would just make an appointment.)

 

See my post dated 11/03/2020 on the old G463 forum that shows where the cabin filter is located, how to open the cover and how to replace the filter element.

 

Here's the link to my post.
https://mbworld.org/forums/g-class-w...placement.html

 

Set a Service Appt - heck, it's not your job to track-it-down - it's THEIR JOB to fix it

 

I would of it was nearby, however it is about a 13hr trip (round trip) to the dealer.