I had just picked up my son from day care and noticed the air was not coming out cold, as i remained driving i hear a "clank" from somewhere in the engine like something came loose and sure enough I looked at my side view mirror and saw something that dropped, circled back to check what it was and it was this ive attached the pics, looks like the front piece that goes on the compressor i didnt find the screw that holds this piece in though please help guys I live in Az it is hot as hell 115 forecast for tomorrow.

 

Click on the image in this link to enlarge and scroll to the bottom to get an idea.
http://www.discountacparts.com/BMW-5...~01984_RC.html#
Your part that fell off fits into the image I've attached.

 

Your compressor clutch fell apart. There are shops that can put a new clutch on, but you risk losing your money if there is something wrong with the compressor. Best advice is to replace the compressor and dryer, refill the system. This needs to be done by a shop with the appropriate equipment. And if you haven't guessed already, no its not cheap.

 

A shop that can replace the compressor clutch can most likely also rebuild or inspect/test the compressor. Just find a shop that specializes in such things.

 

My AC has been working intermitantly on my '08 550i so I took it in for service.

They replaced the compressor and also performed a software update, as both were listed as Service Bulletins.

I wonder if it was the compressor clutch that was going bad?