^yes, you'll need to loosen both bolts. And yes, number 2 from underneath the car. Also yes, there is not much room, even after you remove the belly pan. A 6" extension with a swivel end is your best chance. Harbor freight has them.

You need to loosen #1 a few turns, then #2 is used to move the pulley.

You want this kit as it has the 1/4" drive Torx bit that will get you into the head of #2

46pc 1 4" Drive Socket and Bit Set Metric Hex Pozi Star Phillips Slotted | eBay

You may still need to purchase a set of 1/4" wobble extensions, but you can get these at Advance, AutoZone, Harbor Freight.

I see you mentioned using a T40 from this set, but those two bolts are T45. I tried the T40, it works but alittle loose. T45 was a much better fit. Are you sure the T40 will work?

Also after loosening number 2, how much do I tighten this adjustment bolt? Do I just tighten it as tight as possible? The belt will self tension?

Thanks guys!

I have to assume the T40 comment was for the tensioner bolt and the T45 was for the set bolt. I was a while ago I played with the tensioner.

I never found anything that indicated the belt was a stretch belt, but I recall I found the tensioner fully adjusted. I ran my tensioner in quite a bit, but do not recall bottoming it out.

Go ahead and remove bolt #2 anyway you can or as others have mentioned. Once you have it out, cut a slot in the end (not head) of the bolt. This way, in the future, you can run the bolt in and out with a screwdriver from above and only have to tighten/loosen it from below.

ok, just finished the AC belt. god, that was a royal PITA!!!

I was able to remove the adjustment bolt from the bottom with a few regular 1/4" extensions and a T40 hex bit. The bolt is actually a T45, but there's no way a 3/8" drive socket will fit in that tight space. So I just used the T40 bit and it worked. I bought a set of wobble extensions but end up not needing them.

Removing the adjustment bolt was a little tricky was doable. The hardest part for me was trying to align it just right to bolt it back on. It's not a straight shot as you can see from the picture. The damn pulley was in the way. I think it's almost easier just to loosen the bolt enough to slide the belt ON and then tighten it instead of removing the bolt completely.

Anyways, I did end up removing the bolt and cutting a slot on the end like DavidJ suggested. Now I can loosen it and work from above if I ever end to change the belt again. Hopefully not anytime soon.

Thanks for all your help and tips guys!! :thumbup::thumbup:

Glad you got it done. Normally, you don't need to remove the bolt, just loosen it enough to get the belt off/on like you mentioned. The slot in the end of the bolt will make that task easier.

I took mine to the indy I use. Jobs like this with the right tools take less than an hour. Well worth it IMHO.

AC Belt & Alternator belt install 08 BMW X5 4.8i
 

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.

glad you got it replaced. It was definitely a PITA. Not hard, but frustrating having to work in such a tight spot.