[kerny7678]

05/2015
N20
328i xDrive
124,xxx miles
Stock engine and drive
5k oil changes since 50k
20k ATF changes since 80k
Diff fluid & transfer case fluid not changed
ASS coded off since 60k

Experiencing an issue when under acceleration. Seems to be more present when turning, but attached videos are going pretty straight. I have had this noise for some time now... recently seems to be getting worse.

I appreciate any response you have and can quickly post more videos or pictures.

Heres a bunch of videos some better than others. Apologies for the clunking noise, ignore it. Toolbox in the trunk banging around.

Parked revs engine bay:
https://youtu.be/DxRpPeK3Mhk

Parked revs inside:
https://youtu.be/q-4urGwHOVk

On ramp:
https://youtu.be/KBYIcSg_zaU

60-80 pull:
https://youtu.be/YgFEvENYQS0

standstill start:
https://youtu.be/upPJXLYXegg

standstill start 2 (higher rev):
https://youtu.be/GOZAamjY-Tg

driving:
https://youtu.be/5zWCS8Z9PK4

[RMachuca3d]

sounds exactly like mine, have a listen to my autox run.

you can hear the same whine.

[sspade]

Just listened to all 7 videos. Sounds perfectly normal, like both of mine. The slight whine that you hear sometimes is more than likely the turbo. Nothing to worry about.

[kerny7678]

Originally Posted by RMachuca3d

you can hear the same whine.

Yes, same noise .

This sound does not worry you at all? When I hear it, I cannot help but let off the gas.

[kerny7678]

Originally Posted by sspade

more than likely the turbo.

Turbo more likely to make this noise when under load? I do not hear a thing when revving in neutral.

[Maverickoso]

To determine if the sound is made by the engine (timing chain, oil pump etc) or the pulley system (AC or Alternator), make sure your battery is sufficiently charged and take your accessory pulley off. I was getting a bit of a supercharger whine at 3,000 rpm and above when parked and revving the engine slowly. Took accessory pulley off, did the same slow high revs and no more sound (your battery can provide enough juice to run your car for a very short time).

Sound is either the alternator or AC. AC was off, noise still present. I'm putting in a new alternator today so I'll report back if the high rpm whine is gone.

[kerny7678]

Originally Posted by Maverickoso

I'll report back if the high rpm whine is gone.

Please do. You and me both have obviously read too much about timing non conformance. Even with a 2015 car, I feel like this is a component that should get serviced at some point. Thoughts?

[Maverickoso]

It's a tough call as I saw an old video of someone test launching a 328i and you could hear that whine. There was one other post where the AC was the culprit.

For me, with the hood up, you can REALLY hear the whine in high rpms. At first I thought it may have been the tensioner as it turns slow (was actually fine, was only $34CDN from Rock Auto instead of $156CDN locally).

Yeah, plan on changing out the replacement alternator on my lunch break soon, so won't be long lol.

[Maverickoso]

Darn... yeah, it's most likely the AC. Could very well just how it makes the sound even when new. When driving I barely hear it so there is that. At least I have a new upgraded 210amp alternator now ahha. Just over $300CDN shipped wasn't too bad either. I'll take it.

[kerny7678]

Good price. I'm going to have my shop take a look at it when I'm in there next. Will update if any news.