[bunk48]

So I picked up my cpo 2020 m340i xdrive about 2 weeks ago and Ive noticed this noise when I accelerate.

The car has 29k miles I brought it to the dealership and the SA said he couldnt hear anything.

Some of my buddies that had 335's said it sounds like a wastegate rattle.

She still holds boost fine. Should I bring it to a different service center?

Also on idle you can very slightly hear the noise its a metallic fluttering noise coming from the passenger side of the engine bay.

[k4sh_90]

Sounds like regular B58 to me

[xnick101]

Sounds normal to me. The B58 also has a wastegate actuator so it should not have wastegate rattle.

[hayko_M340]

Is the car tuned or have a catless downpipe? Nearing 32k miles and I also have developed a metallic fluttering/whooshing sound coming from turbo area very hard to describe the noise but definitely not there previously and gradually increased. Check out this other post on the forum and his video, mine sounds identical. I honestly think it's normal especially if you drive it hard and as miles rack up and various heat cycles, no harm done still holds boost fine and rips. Tons of people with high mileage running aggressive tunes, bolt-ons, upgraded fueling you name it on stock turbos and the B58's seem to hold fine. A lot of the noise is also from the High Pressure Fuel Pump especially with these direct injection engines they make a lot of noise.
Link to videos:

[bunk48]

Originally Posted by hayko_M340

Is the car tuned or have a catless downpipe? Nearing 32k miles and I also have developed a metallic fluttering/whooshing sound coming from turbo area very hard to describe the noise but definitely not there previously and gradually increased. Check out this other post on the forum and his video, mine sounds identical. I honestly think it's normal especially if you drive it hard and as miles rack up and various heat cycles, no harm done still holds boost fine and rips. Tons of people with high mileage running aggressive tunes, bolt-ons, upgraded fueling you name it on stock turbos and the B58's seem to hold fine. A lot of the noise is also from the High Pressure Fuel Pump especially with these direct injection engines they make a lot of noise.
Link to videos:

So 2 service centers later they all say its fine. My buddy picked me up in his lower mileage 2020 and the noise was not there. The car still runs fine and holds boost so at this point I can live with it I guess. Cruising in traffic is very annoying but whatever.

[Levi340]

Originally Posted by bunk48

So 2 service centers later they all say its fine. My buddy picked me up in his lower mileage 2020 and the noise was not there. The car still runs fine and holds boost so at this point I can live with it I guess. Cruising in traffic is very annoying but whatever.

Any update brother ?

[WDE82]

Posting here just to bump the thread a bit even though I have an '18 F36.

This seems to be something with the design of the B58 wastegate actuator linkage. I can reach in and touch mine and I'm sure it's the source of the rattle I can hear when driving near a wall with the windows down. Has anyone devised a fix to this? It's definitely not a real problem and not what the N54/55 turbos experience with the valve bushing itself wearing out. However this does appear to be a common noise source on other cars.

The linkage has play in both of these joints (red arrows). The left joint is secured with a clip and can be removed but the right joint is permanently riveted and is a part of the wastegate actuator assembly (11658662676).

Two ideas come to mind to fix or reduce the rattle:

1. Add some kind of spring clip to both joints to press the pushrod to one side thereby stopping it from shaking around and causing noise
2. Add some mass to the pushrod such that it changes how the pushrod bounces around and causes noise.

Something like this

I may measure the pin diameters and order these

https://www.mcmaster.com/products/cl...taining-rings/

[Dom007]

Any reason why this sound would only be occurring in Comfort or Eco mode? I have it on my 2021 M340i as well but when I put engine to sport it goes away 😂