I have been battling with this high pitched squealing noise coming from somewhere within the engine bay of my 2012 JCW R56 for the past few weeks. It is very hard to pinpoint where the sound is coming from due to the sound only occurring while driving and stepping on the gas going between 4,000 RPM to redline, and will get a higher and higher pitch until reaching redline. No squealing while idling or under 4,000 RPM. I would think if it was the water pump or tension pulleys it would do it more constantly or at lower RPM. The S-belt was replaced only 10,000 miles ago so I very unlikely it is that. Could it be a diverter valve or some type of boost leak to not give a check engine light or any decrease in power? If anyone has ideas or opinions I would appreciate the help! Thanks!

 

 

I wish I could have someone do that but it's only when I am driving it from 4,000rpm to redline, it won't make the sound just revving it up. My apology on not making that clear and sorry for posting in the wrong forum, very new to this.

 

Do you smell anything burning associated to the noise? I'm asking since I'm wondering if it may not be some kind of clutch / flywheel / pressure plate issue since the sound only appears to happen when the clutch is disengaged (motor in gear with clutch pedal not depressed at high RPM)

Could also be a loose belt that's slipping under the increase load of high RPM