N55 Vibration Damper noise

[apollard]

I've been chasing an intermittent noise from the belt on my 2012 X5 with N55 engine. I did the normal things first:

Changed belt and idlers - none had any resistance and turned smooth
Checked accessories - all turn smooth, no evidence of bearing issues, etc.

After doing this, it seemed the noise was less frequent, but still would do it sometimes. Then it went away for several months.

This summer, it came back, but wouldn't always squeal. Now, I can replicate it everytime. It only make the noise when the engine is hot. If allowed to cool to close to ambient, it won't squeal. Warm / Hot, it always squeals. If you rev the engine above 3,000 rpm it goes away and doesn't come back until you stop it and restart hot. It will repeat that pattern as many times as you want to start / rev up / stop.

So I crawled under with the engine cold and the vibration damper is clearly wobbling. Heated her up, restart and the noise is there. I can tell the noise is centered on the crankshaft area.

Here's a video I took that gives noise and the damper wobble.
Edit: couldn't get embed to work-

https://www.youtube.com/watch?v=19-B...ature=youtu.be

On my phone it is slo-mo and the noise is clearly timed with the wobble. On Youtube if you set it to 0.25 playback speed it isn't as easy to see the timing, but it's there.

So, it seems my vibration damper is shot and causing the squeal. Odd that it only does it hot and after revving it goes away until restart. I found one video for an F30 that seemed similar, but searching didn't show anything else. Maybe I just used the wrong terms?

Before I replace $650 parts, Is this a common or known issue?