n1tr0_9

Dear all,

i found the site whilst trying to diagnose an engine noise that has developed on my 530d. Its a 2009 with 126k on the clock.

It has developed a whirring whining noise. It is only really audible at low engine speeds. The pitch and volume increase and decrease with engine speed.

Gear selection or vehicle speed or engine load make no difference.

It sounds like the power steering system, is low or similar, but it is not. Turning the steering wheel on full lock almost no difference to the noise.

Ive tried switching on and off the aircon, but that makes no difference. Its not alternator either as i put all lights, rear window heater, stereo on and the noise stays the same.

The noise sounds like its coming from the nearside of the engine, but i cant see anything obvious. Any suggestions please? Or links to videos of similar noises?

Any help would be very much appreciated!

Thanks

I have put a video on youtube here:

https://www.youtube.com/watch?v=sU7Z...ature=youtu.be

n1tr0_9

I have made some progress. i removed the aircon belt. No change in the noise.

I then removed aux belt and the noise went away (only ran it for a few secs obviously).

The tensioner idler felt nasty, so did the idler that goes under the alternator. I removed the idler from under the alternator, and refitted the belt, as it doesnt really touch the idler much. Noise came back.

So its either...water pump, power steering, vibration damper, tensioner idler or airpump. Anyone got any good ideas as how to test the others as they all feel fine to the touch?

n1tr0_9

I didnt get any replies, but just to help others, it was the alternator. I made some more videos of further diagnostics and how to swap the alternator.