Strange High Pitch noise seems to be coming from rear (4.8is) - any idea's???

[Lion Heart]

Hi guys!

Ok, so following up on this...

I mnaged to get the car on a ramp, went underneath with the engine running and the high pitched noise definitely seemed to be coming from the bottom of the fuel tank area. And it was also accompanied by a grinding/scratching kind of noise as well.

So, my thoughts get the fuel pump changed ASAP.

So fitted a brand new fuel pump (not too bad a job to do to be fair). The high pitched noise has now gone (hooray!) but that grinding/scratching noise is still there and does not sound very nice.

You do need to be close to the underside of the fuel tank to hear it, you cannot hear it inside or outside the car AT ALL unless you're within a few inches of the underside of the fuel tank.

I've taken a video and would really welcome some opinions on it...

https://www.dropbox.com/s/mk41qg13ana8w4h/BMW%20X5%20Fuel%20Tank%20Scratching%20Grinding%20N oise.mp4?dl=0

You can hear it quite clearly grinding/scratching when I zoom in close to the bottom of the tank.

Now, that's a brand new fuel pump and it did this same noise before and after the pump change, so I would think it must be something else? Is this noise normal?????