2011 X5 35d diesel engine noise

[lintao2002]

2011 BMX X5 35d 130k miles, recently has engine noise.
I took a video here

https://youtu.be/je7jq7FWZYk

Any idea what the issue is or where the noise comes from?

[crystalworks]

The "whirring" noise? Sounds pulley or belt related. Maybe an idler or tensioner pulley? Won't know for sure until you do some diagnosis. You can remove the belt and see if the noise goes away... that's usually the first step.

Or, you could try spraying some WD40 on the belt and pulleys to see if the noise changes tone or goes away completely. You should clean the WD40 off after the test.

[workingonit]

I've heard that sound when I let a truck sit for months, and the converter lost most of its' already low fluid level (it was sitting at a steep angle).

Here's a YouTube clip of an TSX with a similar sound:
https://www.youtube.com/watch?v=4b-IdCIb_D0

[sgrice]

Here is what I posted over on Bimmerfest forum:


So it sounds like only happens when revving the engine? Like around 2K rpm?

The obvious thought is something to do with the serpentine belt, pulley bearing, or tensioner. To rule some portion of the serpentine belt in or out one would loosen the tensioner, remove the serpentine belt, have it carefully held out of the way while the engine is revved and see if the noise is still there. If it goes away, then I would replace belt, pulley, then tensioner in that order.

However, given this is an M57 diesel engine, I would be very suspicious of a broken or loose exhaust manifold stud with leakage of exhaust gas (and hence whistling/whining) at higher rpms. You can use a borescope to check for loose/missing studs/nuts. There are numerous examples of this on various forum postings. The most recent one was on this [sic - Bimmerfest] forum just a few weeks ago. You can read about it here. Be sure to read all the various links in the posting. Lot of good information there.

Of course, could be a bad turbo, alternator bearing, ac compressor, etc. But common things are common, and my money is on the exhaust manifold.

Good luck. Let us know what you find.