video:

https://video.fybz2-2.fna.fbcdn.net/v/t ... e=5DBF652E

Looking for some insight into what this sound could be, I figure alternator pulley, idler pulley, water pump or timing chain issue. I deleted the upper idler pulley as it was worn out but that was not the cause, not running ac belt to rule that out as well.

Just happened this past friday, the alternator is only a year old but the pulley does have very slight wobble, idler pulley is newer as well. turning the bearings by hand they seemed okay. Water pump has never been changed as far as I know, could that be the cause or could it even be timing chain guides?

Would I be OK to start the car with no belts to rule out timing chain? sounds similiar to some bad alternator bearing videos im seeing

The video link didn't work for me. It says the URL expired.

Is this problem on a V8 or V6? Please specify the year as well.

And yeah, you can run the engine without belts. When I've done it, I made sure it didn't run for too long for the sake of keeping the battery charged (alternator) and for cooling purposes as well.
The battery would run out soon enough anyway, just keep a booster handy.

I did confirm it to be the alternator bearing. Seized up. Oddly, the noise went away today (unfortunately no choice but to drive it to work today), then noise came back after an hour of driving. Today right before I pulled into my driveway, bearing seized up and the belt broke. Made it home lol, not driving it until its fixed. Happy its just a bearing

To clarify, 2006 M35, ill repost the video in case anyone else has the same sound.

Thank you for coming back and updating...many users don't. Good stuff.

Oh np, I should do writeups lol. Driving this thing 300km a day has me fixing things weekly. Need a new car for this job.

I ended up swapping the old alternator out with a used oem one. I probably should have gone that route originally vs buying a new off brand one since that only lasted a year, $75. The alternator is working correctly. Installation was quite simple though i didnt fasten the metal backing plate to the rear of the alternator because theres just no room and it seemed redundant

Interestingly, My audio cut out some time ago. When I installed the 'new' alternator and went for a drive, the audio worked for a good 15 minutes and cut out again. I thought it was my amp but now I have no idea. It worked great then stuttured a bit, cut out and wont turn on now. Loses radio feeds as well.

Is that any indication as to the audio issue? I suppose it was related to the computer resetting while i had the battery cables off. I was thinking the amp blew but as mentioned it worked great then cut out!