What a PITA!!!!!! I was fortunate enough to change both my AC and alternator belts on my 08 BMW X5 4.8i (94k), two days ago (Saturday) from the post date. Thanks to all the post/pics from others like gregg3gs and lordshin88 that gave me the courage to attempt this task.

I would like to share some tips from my experience. The serpentine belt (alternator belt) has one adjusting bolt, which is a Torx T60 bit, which is spring loaded-eventually the easiest of the two belts. The AC belt has two adjusting bolts as pic's here on this site has noted and describe them as bolts #1 and #2. Bolt #1 was I believe a Torx T45 and reached from the top of the vehicle, and bolt #2 underneath the vehicle is a Torx T40. This AC bolt #2, underneath the vehicle is the PITA working in very tight space. There was enough room underneath for me move the pulley with a finger tip towards the front of the vehicle using one hand to clear a very small amount of space, and the other hand to ease the extension up towards the bolt head.(Of course bold #1 on the AC should already be loose to get this small amount of movement), I was able I to increase my chances of a clearer pathway to get my 3/8 universal and extension at the bolt the head #2. It was still a "very-very" tight space and it took many exhausting attempts getting enough revolutions on bolt #2 to eventually tighten up the AC belt. I hope this little bit of suggested information helps some one.