[DickBlisken]

Originally Posted by StannisBaratheon

Just came across this thread and I've experienced the same noise since I've owned my 2016 340i. It's been to the dealer before for wastegate ticking noise on cold start (it's more noticeable in cold weather) but BMW said it's normal.

Car is going back to the dealer next week for inspection and low coolant so maybe they can look at this fluttering noise again.

Also have experienced the same sound on my 2016 340iX with 17,000km

Surely this can't be a turbo related issue at such low mileage?

[daac]

Originally Posted by StannisBaratheon

Just came across this thread and I've experienced the same noise since I've owned my 2016 340i. It's been to the dealer before for wastegate ticking noise on cold start (it's more noticeable in cold weather) but BMW said it's normal.

Car is going back to the dealer next week for inspection and low coolant so maybe they can look at this fluttering noise again.

mine has always ticked on cold start but my issue was mostly partial throttle. It definitely sounds smooth after the repair was done. They sure tried their best to not fix it tho. 3 visits over several weeks as they kept saying they fixed it but didnt. I had to be persistent and ask for the shop foreman to go on a drive to show him the sound. they finally bucked up and I ordered a new Turbo.

[StannisBaratheon]

Originally Posted by daac

mine has always ticked on cold start but my issue was mostly partial throttle. It definitely sounds smooth after the repair was done. They sure tried their best to not fix it tho. 3 visits over several weeks as they kept saying they fixed it but didnt. I had to be persistent and ask for the shop foreman to go on a drive to show him the sound. they finally bucked up and I ordered a new Turbo.

Just dropped it off, this is the second trip to the dealer for the noise so we'll see what happens. Also the second time it's been in for low coolant. I'm anticipating they'll top up the coolant and say everything looks normal with the turbo.

[DickBlisken]

I purchased my 340ix just over a month ago from a major BMW dealership in my city. Came with a fully-clean inspection report, carfax, and assurances from them that the car was in good health. At the time of sale, the car was 1 month out of warranty.

Haven't put 1000km on it myself since taking ownership, and noticed the fluttering sound in my parking garage about 2 weeks ago. Thought it was normal, as everything was/is operating great.

Going to be interesting to see what they have to say...

[StannisBaratheon]

Originally Posted by DickBlisken

I purchased my 340ix just over a month ago from a major BMW dealership in my city. Came with a fully-clean inspection report, carfax, and assurances from them that the car was in good health. At the time of sale, the car was 1 month out of warranty.

Haven't put 1000km on it myself since taking ownership, and noticed the fluttering sound in my parking garage about 2 weeks ago. Thought it was normal, as everything was/is operating great.

Going to be interesting to see what they have to say...

Other than the noise, does it feel down on power? I wish I had another 340ix to drive side by side to tell if this wastegate noise is having an impact on performance.

Edit: Just heard back from the dealer and they're still diagnosing the turbo rattle but my water pump is leaking so it sounds like that will be replaced. Should be covered under CPO warranty.

[DickBlisken]

Originally Posted by StannisBaratheon

Other than the noise, does it feel down on power? I wish I had another 340ix to drive side by side to tell if this wastegate noise is having an impact on performance.

It does not. Car runs very smooth and feels more lively than ever.

[DickBlisken]

I should also add that, similarly to OP, the noise is most prevalent while the car is cold, during takeoff. It seems to disappear (or at least become so quiet that it's not immediately noticeable) when the car is warm.

I've tried to reproduce it for a friend, after driving 10km to their house, and they thought I was crazy.

[DickBlisken]

Also, isn't wastegate rattle typically more of a mechanical 'chattering' while the revs are decelerating?

[Sleeper340i]

I've been dealing with this issue for the last month or two. Had the same exact sound as OP so I got the wastegate/manifold replaced by Pure Turbos (was a Pure 800 turbo) which completely fixed the problem and the sound is gone, so in my experience it is 100% the wastegate.

The sound does not resemble the N54 wastegate rattle from what I've seen on YouTube, but my cold starts would be very noisy like a exhaust manifold gasket leak. In my experience sound got worse over time and I could even hear it on WOT, downshift, up shift, but mainly any time my foot was lightly /mid way on the pedal. Was embarrassing to drive around with lol.

[Sleeper340i]

Here is a clip of mine where you could hear the same sound as OP, mainly in the second half of the vid. Over time the sound got even worse than in the vid.

[DickBlisken]

Check out this thread from a German forum. 7 pages of B58 drivers reporting the same issue: https://www.1erforum.de/threads/b58-...asseln.243416/

There's mention of the noise returning 2,000km after a new turbo replacement.

Be sure to translate the thread to English

[DickBlisken]

... As well as a thread from the SupraMKV forum, also regarding the B58 flutter: https://www.supramkv.com/threads/cha...2021-a91.5810/

[Senhorcheeks435]

[Dr. Avit Grey]

Originally Posted by daac

ok here's a video clip of mostly my hand but the audio is pretty clear the fluttering noise I am referring too. Hard to tell if the frequency increases with engine RPM. I was driving next to concrete dividers with the passenger side window down

So back to shop it goes today. I will update when I have some info.

Did you ever get this sorted out?

[SimonO]

I have the same noise too. It seems to disappear or become much more quiet under the same conditions but in Sport mode. Definitely more noticeable in Comfort mode

[Dr. Avit Grey]

Bumping to see if anyone can shed some light on this fluttering.

My daership says it's the injector pulse harmonizing. But that's bullshit as the flutter isn't linear with the rpms, it's close but not quite inline.

[vrships]

Thanks very much for OP to dig out the truth.

I heard the exact same noise on my Gen2 B58 on the x3 m40i. I flashed the car with BM3 after it went our of warranty and have since noticed the noise ( maybe it was there before jfbut I just didn't catch). It is most obvious when accelerating mildly from 1.5 to 2.5k rpm and doesn't change much hot or cold.

The car still runs fine and I tried all maps and the it pulls so powerfully and consistently so far so maybe it's not affecting anything (yet).

One thing i could possibly relate to why this happens is that the BM3 maps have much higher boost target for this engine at 22.1 psi, but when the car runs and shifts, momentarily actual boost can reach 28 psi for a split of second and the wastegate needs to act aggressively and over time it stresses the mechanical lineage too much so it's not as tight as before.

I wonder if there s an easy fix for this, like replacing the wastgate module only without touching the turbo. Or maybe it is not an issue in the long run.

[LAM340I]

Anyone have an update?

[DickBlisken]

100,000 km later, still the exact same. Fluttering on cold start, gradually goes away. Car still drives amazing.