Removing Engine Cover - Bolt stripped/slipping

[Bolderboulder]

The driver's side bolt securing the engine cover is either stripped or slipping. It turns but will not back out. I tried applying upward pressure to that side of the engine cover while loosening the nut, but that did not work. I sprayed some Liquid Wrench on it but that did not help.
Aside from carefully cutting the cover's plastic as close around that nut as possible to remove the cover, does anyone here have suggestions?

I would greatly appreciate it!

 

[Bigshankhank]

Gotta think you could score a replacement engine cover from a junkyard fairly easily, so cutting out around that bolt probably wouldn't be too earth-shattering.
Something else you could try is getting a 1/8" cobalt-tipped drill but and drilling around the edge of the nut until it breaks apart. Time consuming though.

 

[AuSeeker]

Drill or grind the head of the bolt off and then drill out the remaining part of the bolt, then retap the hole if it's not stripped, if it is stripped then drill it a bit bigger and retap the next size up.

 

[rdruss]

I think what's happening is the stud that the nut screws on to has broken loose from the bracket and the stud is turning. See if you can reach under the cover with a pair of needle nose and grasp the stud and then turn the nut.

 

[BackOff]

I think what's happening is the stud that the nut screws on to has broken loose from the bracket and the stud is turning. See if you can reach under the cover with a pair of needle nose and grasp the stud and then turn the nut.

Yup this.
Its basically a bolt glued to a rubber spacer and another bolt glued to the other side.
They come unbonded.
The cover may just pull up.

 

[Bolderboulder]

Yup this.
Its basically a bolt glued to a rubber spacer and another bolt glued to the other side.
They come unbonded.
The cover may just pull up.

Thanks everyone! I used a small, curved blade chisel to score the plastic surrounding the bolt, then gently pulled upward on the cover and that stuck bolt slid through the scored plastic.
The culprit was that bolt's metal sleeve in the cover. Someone had tried to pull the cover off without removing the bolt and that metal sleeve became dislodged in the cover.
The cover came off, I degreased the top area of the engine and the engine cover, cleaned the cover with denatured alcohol, applied a coat of "The Black Stuff," and then a coat of ceramic coating. I also cleaned the Mass Air Flow sensor.