Can't remove acoustic cover

[Perrier]

On my 2004 X5 3.0,

The rear nut on the acoustic cover over the valve cover refuses to release. I have sprayed it with wd40 for a few days, used air ratchet, manual ratchet, but all I get is what feels like a gummy twist until ratchet has no more room. It is as if it is spinning the metal bracket with the rubber base, so the rubber has some give. This may be the case unless there's a wire hooked to it under the cover.
Any one with ideas?
I hope I don't have to destroy and replace the cover.

[David.X5]

I would start by tightening the other fasteners to remove the tension on the one that seems to be spinning.

You should be able to get a flexible inspection camera under the cover to see what is going wrong.

[Calipsoe]

It's a rubber mount between the beauty cover and the valve cover. You may be able to get a grip on the bolt with pliers while turning the nut although you may damage the threads. The alternative is to twist the nut with enough force to tear the rubber bushing apart and just replace it. They are cheap. Part Number = 11121730356

Look here and you'll see what it is your dealing with.
Auto Pro. Cylinder Head Cover Rubber Mounting BMW Engine M50 M52 M54 E34 E36 E46 E38 E39 E60 E61 E65 E66 320i 323i 325i 520i 525i 530i 728i 730Li

[upallnight]

Most likely some amateur cross threaded the stud already, that's is why the nut is so hard to come off.