[m340iyup]

Hello, I got my 2020 m340 5 weeks ago, and recently I started it (Cold start) and decided to get something from the back seat, I heard a whistle coming from the engine (Video attached), it quiets quiets down as you can see in the video, and then it completely goes away. When I'm in the cabin I don't hear it, that's why I only noticed it when I was outside. It only happens on cold starts.

I'm scheduled for an oil change in couple of days, and have warranty, but just wanted to see if anyone else has this sound?

Video: https://streamable.com/rplxiv

[siphor1989]

I have a 2020 m340i and it has the same exact whistle on cold start. It quiets down a lot when warmed up but there is still a very faint, barely noticeable whistle at idle. I’m also interested in knowing if this is normal or not.

[m340iyup]

Originally Posted by siphor1989

I have a 2020 m340i and it has the same exact whistle on cold start. It quiets down a lot when warmed up but there is still a very faint, barely noticeable whistle at idle. I’m also interested in knowing if this is normal or not.

Yup same exact, at cold start it's very noticeable, then it cools down just like in the video. Then by the time I leave my parking lot, and I'm outside, I barely notice it/ don't hear it.

[m340iyup]

BMW tech just texted me saying "I don't hear anything, I hear a normal engine and exhaust" how can you not hear the whistle? unless he deems that normal? can someone please chime in. 2020 m340i.

[Das_Stiggy]

It's the turbo lol

[hayko_M340]

That's weird, never heard that on my 20'. Nearing 43K miles.

[m340iyup]

Originally Posted by Das_Stiggy

It's the turbo lol

That's what I thought at first, but the sound is coming from the right side, no turbo there. On the left side it's completely silent as you see in the video. Maybe I'm wrong lol, my first BMW.

[rusty_g80]

Mine does the exact same thing. I’m thinking it may be PCV related. Does your exhaust smell like gasoline?
I did take my car to a dealer, but as usual with this dealer they cannot replicate anything. I’ll take it to another dealer in couple of weeks.