Whistling sound at WOT?
Thread Starter
Junior Member
Joined: Aug 2010
Posts: 49
Likes: 13
From: Los Angeles
'18 C63s Coupe
Whistling sound at WOT?
I'm getting this high-pitched whistling sound that only happens at wide open throttle between 2nd - 3rd gear. 2018 C63S. Doesn't seem like there's any loss in power, but still seems odd.
Anyone else experience this?
Anyone else experience this?
Junior Member
Joined: Jan 2019
Posts: 42
Likes: 7
C63
https://mbworld.org/forums/c63-c63s-...ml#post8099413
https://mbworld.org/forums/c63-c63s-...ml#post8102493
Have a read of the above, possibly the same noise, probably “normal”. My car is a 2018 PFL
https://mbworld.org/forums/c63-c63s-...ml#post8102493
Have a read of the above, possibly the same noise, probably “normal”. My car is a 2018 PFL
Senior Member
Joined: Jun 2019
Posts: 453
Likes: 91
From: DFW, Texas
2017 AMG C63
The whistling symptoms could be caused by the air at a certain load/rpm/boost combo that happens to create a whistling effect - but would still bet it is leaking at other times as well. ( If it is in fact a vacuum leak)
It is not surprising that you would not notice a loss of power if the leak is small.
I would start with the easy free stuff like checking/tightening all vacuum hoses for wear holes, clamps, bolts and operation of bypass valves, etc.
If you can't Identify it, just take it to a qualified shop and they will probably do a vacuum or smoke test.
Edit: After reading the 2 threads above, I have actually had that symptom intermittently as well over the last 2 years. Same thing happens at WOT, high rpm, not every time. I can hear it, then do the same pool immediately afterwards, its gone.
I have tossed around 2 theories:
1. It is the blowoff valve leaking at max load/stress, especially if running a tune with higher boost levels.
2. It is the ECM/traction control interfering is some specific circmstances through electronic manipulation of the bypass valves, in order to help maintain traction or something. Idon't think it's ever happened with the traction control fully off, and does seem to happen more when immediately preceded by tire spin, especially when turning. Unfortunately due to the intermittent nature of the whine and the fact I rarely drive around with the traction control fully off, that may just be coincidence or obsevation bias.
I still suggest the same course of actions I mentioned above though, even if just to eliminate the possibility of a vacuum leak.
Last edited by LessIsMore; Jun 11, 2021 at 01:23 AM.
Super Member
Joined: Jan 2020
Posts: 544
Likes: 228
From: Sydney
C63 S Coupe
It only happens just after a cold start?
Anyone else notice this high pitched heeee noise on WOT only happens after a cold start but eventually goes away after the car is really warmed up and driven it hard?
I heard it today and it disappeared after I gave it a good flogging in Sport+ mode 🤔🤔🤔
I'm really leaning towards pulleys and belts. Going to try again tomorrow with the aircon off..........
I heard it today and it disappeared after I gave it a good flogging in Sport+ mode 🤔🤔🤔
I'm really leaning towards pulleys and belts. Going to try again tomorrow with the aircon off..........
Junior Member
Joined: Sep 2016
Posts: 27
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M3
Squeak/ Squeel on 3rd gear upshift WOT
Hey everyone I recently hit 29k miles on my 2018 C63s and started noticing a weird sound on WOT up shift when I click the paddle.
Its a very faint squeak or like "heeee" sound from what sounds like the area right behind the upper dash area or behind the gauge cluster which would be the upper portion of the air boxes in the engine bay. Its only in 3rd gear when I use the paddle shift or full Manual mode Sport plus or Race mode. Only mods are AFE Pro dry drop in filters and I feel like it just started recently doing this sound. Ive had the filters in for about 1000 miles but other than the weird sound only WOT near redline shifts in 3rd gear I cant hear anything else. Any help on what to inspect or information would be greatly appreciated. I might swap back in the OEM filters to see if it still makes the sound for my first test to narrow anything down. Im going to try to do some WOT pulls and let the car shift on its own and listen to see if it makes the sound in auto mode as Ive only heard it while in Manual mode or auto but manually shifing.
Its a very faint squeak or like "heeee" sound from what sounds like the area right behind the upper dash area or behind the gauge cluster which would be the upper portion of the air boxes in the engine bay. Its only in 3rd gear when I use the paddle shift or full Manual mode Sport plus or Race mode. Only mods are AFE Pro dry drop in filters and I feel like it just started recently doing this sound. Ive had the filters in for about 1000 miles but other than the weird sound only WOT near redline shifts in 3rd gear I cant hear anything else. Any help on what to inspect or information would be greatly appreciated. I might swap back in the OEM filters to see if it still makes the sound for my first test to narrow anything down. Im going to try to do some WOT pulls and let the car shift on its own and listen to see if it makes the sound in auto mode as Ive only heard it while in Manual mode or auto but manually shifing.
Last edited by shane060; Jul 18, 2022 at 01:00 PM.
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Unlikely the cause but check your air intakes as well, if you are not getting full boost at WOT, then it might be a loose air intake, the plastics are super flimsy and so easy to to be unclipped or not clipped on properly when doing an oil change for example. The sound of which that forum member described as a "dentist drill", not the same model, c43 vs c63s but very similar air intake design in the c63s with those plastic clips. https://mbworld.org/forums/c450-c43-...ml#post7825169
Thread Starter
Junior Member
Joined: Aug 2010
Posts: 49
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From: Los Angeles
'18 C63s Coupe
In case it helps someone else, this sound ended up disappearing after I got my transmission serviced. Still not sure why it was happening, but it seems that simply changing the transmission fluid & filter solved the problem.
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Hmmm might be incorrect level then but glad it got solved thanks for the update.
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From: Australia
⏱️ 700HP Facelift converted C63 S Coupe with Drexler 3.06 plated LSD
Can 100% confirm this is the stock turbochargers now because after I changed the turbos in mine I never heard this whistle again. But don't worry too much my Coupe had this whistle noise from almost new and I drove it hard like that for 30,000 miles and they never missed a beat. It's just one of those irks.
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Can 100% confirm this is the stock turbochargers now because after I changed the turbos in mine I never heard this whistle again. But don't worry too much my Coupe had this whistle noise from almost new and I drove it hard like that for 30,000 miles and they never missed a beat. It's just one of those irks.
