[RiverDude]

2016 320i 103k miles

I am hearing a strange intermittent engine noise at startup. I d'ont think it is the timing chain whine of death because i have listened to posts of that. Mine is more like a banshee screech. Comes and goes at low engine RPM while in transmission is in park. Does anyone have any ideas what the cause could be. I just change the oil about 1000 miles ago and confirmed the level was good this morning. Coolant level is good and i flush and replaced the coolant about 18 months ago.

Attached zip with MP4 of the sound.

[Billfitz]

I couldn't hear it well enough. Open the hood, record it from in front of the car.

[RiverDude]

I rerecorded the sound and I think I got a good recording now. Of coarse it did not want to make the noise but I got it.

Few notes about this recording. I have clipped the video/sound length to just the needing few seconds. At the start of the clip the engine is already on. The oil cap is off. I thought that would help if it was a timing chain noise. The recording device is sitting on a towel on top of the engine battery jump start connection cover. Engine was not making the noise then I put the oil cap on at 1 second into recording and at 2 seconds the screech noise (or maybe wheeze) occurs.

Any ideas what is causing that noise? Thanks for taking the time to read and listen.

[Billfitz]

It's not timing chain. PCV diaphragm is a possibility. It's not expensive, so worth giving it a shot. https://www.amazon.com/Engine-Valve-.../dp/B07XPW6XVV

[RiverDude]

Thank you for the quick reply. Part ordered. I will update in a couple of weeks.

[Billfitz]

It may not be that, but at 103k it's not a bad idea to replace it anyway. For that matter everything made of rubber and subject to heat is reaching end of life.

[RiverDude]

Replaced it today. The old PcV was looking pretty bad and fell apart when i removed it. Thanks for the help.