high-pitched whistling sound




2020 GLS and mine is doing the same thing and it aggravates the hell out of me considering how expensive this vehicle is and it’s supposed to be the S class of SUVs!! I told the dealer after I purchased it but I’m two hours away so multiple trips it’s not really something I’m looking forward to!!
I have noticed that debris in the foam around the front of the front doors sometimes is a little crooked. You have to straighten it. Dust/dirt/gravel can get in there as well. Once you attend to it, just put a bit of silicone spray on them and the sound goes away. Same inside the hood around the engine isolation foam.
I have noticed that debris in the foam around the front of the front doors sometimes is a little crooked. You have to straighten it. Dust/dirt/gravel can get in there as well. Once you attend to it, just put a bit of silicone spray on them and the sound goes away. Same inside the hood around the engine isolation foam.
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Last edited by MuddyBlueJeans; Jan 24, 2021 at 11:06 AM.
After I came across this thread I understood it’s not just some random noise and there are lot of people with the issue.
Its F**** crazy to have such noise, Acoustic package supposed to make the car quieter not sure what’s going on.

https://www.aliexpress.com/item/4000...archweb201603_
My dealership refused to fix the issue in the beginning. After I told them it's one of hot topics at MBWorld forum and showed them the LI88.70-P-071478 tip I got from this thread, they did something according to the tip, but the noise didn't disappear (the dealership claimed there's no more noise, which wasn't true.).
I did the taping experiment myself. I used this one from Amazon to put tape around the side mirror. It turned out that the noise is gone with the taping.
Next, I removed pieces of tape one by one until the noise returns.
The photo below is with minimal pieces of tape with no noise. If you remove any of them, the noise comes back.
Note that there are two pieces of tape.
From another Mercedes forum (in non-English), I got to know that many people were able to eliminate the noise after the carbon-look cover is put on.
They ordered the cover for cosmetic purpose and found it fixes the noise issue as a by-product. I placed an order, put it on, and the noise disappeared!!
I am under impression that it's by pure luck. It changes the air flow around the side mirror.
I also think that the cases reporting that the dealership was able to fix it was also by pure luck. It seems that MB doesn't know how to fix it and something needs to be slightly changed around the mirror to redirect the air flow.
The cover turned out to be one way of doing that which worked for me, but may not be universally applicable to all cases (in that MB forum, there's one person who wasn't able to fix the noise issue even with the cover.).
Last edited by GLEowner; Dec 26, 2020 at 05:39 PM.
https://www.aliexpress.com/item/4000...archweb201603_
My dealership refused to fix the issue in the beginning. After I told them it's one of hot topics at MBWorld forum and showed them the LI88.70-P-071478 tip I got from this thread, they did something according to the tip, but the noise didn't disappear (the dealership claimed there's no more noise, which wasn't true.).
I did the taping experiment myself. I used this one from Amazon to put tape around the side mirror. It turned out that the noise is gone with the taping.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
Next, I removed pieces of tape one by one until the noise returns.
The photo below is with minimal pieces of tape with no noise. If you remove any of them, the noise comes back.
Note that there are two pieces of tape.
From another Mercedes forum (in non-English), I got to know that many people were able to eliminate the noise after the carbon-look cover is put on.
They ordered the cover for cosmetic purpose and found it fixes the noise issue as a by-product. I placed an order, put it on, and the noise disappeared!!
I am under impression that it's by pure luck. It changes the air flow around the side mirror.
I also think that the cases reported that the dealership was able to fix it was also by pure luck. It seems that MB doesn't know how to fix it and something needs to be slightly changed around the mirror to redirect the air flow.
The cover turned out to be one way of doing that which worked for me, but may not be universally applicable to all cases (in that MB forum, there's one person who wasn't able to fix the noise issue even with the cover.).
Overall I like the look. It doesn't look fake.
It comes with additional 3M tapes but I managed to put the covers on at the first attempt. It's a little tricky to position the cover right but not that difficult.
I am not sure if any residues would remain if the covers are removed later.
My suggestion is to confirm that the noise is gone with some taping first to make sure the air flow around the side mirror is the cause.
You also need to drive with the side mirror folded. That's actually the 1st thing to try.
Note that the side mirror won't be folded while driving fast, so you need to slow down enough (almost stopping) to fold it and speed up to test.
It's a little dangerous to drive onto the freeway ramp with the side mirror folded. Please drive extremely cautiously. That's what I did.
Last edited by GLEowner; Dec 26, 2020 at 12:12 AM.
It comes with additional 3M tapes but I managed to put the covers on at the first attempt. It's a little tricky to position the cover right but not that difficult.
I am not sure if any residues would remain if the covers are removed later.
My suggestion is to confirm that the noise is gone with some taping first to make sure the air flow around the side mirror is the cause.
You also need to drive with the side mirror folded. That's actually the 1st thing to try.
Note that the side mirror won't be folded while driving fast, so you need to slow down enough (almost stopping) to fold it and speed up to test.
It's a little dangerous to drive onto the freeway ramp with the side mirror folded. Please drive extremely cautiously. That's what I did.
The issue on my car is definitely coming from the mirror housing, so maybe this fix can be a two birds with one stone fix. Do you mind linking or DM-ing me the link to the foreign language forum that they talked about this housing cover fixing the wind noise? I would like to read more on that. Thanks!
I am not sure what to do?
The issue on my car is definitely coming from the mirror housing, so maybe this fix can be a two birds with one stone fix. Do you mind linking or DM-ing me the link to the foreign language forum that they talked about this housing cover fixing the wind noise? I would like to read more on that. Thanks!
I would check with the dealership if the side mirrors of GLE and GLS are exactly the same. If so, it's safe to try the covers.





