You'll have to be pretty handy and have a good collection of tools to tackle this job. Here are the instructions with as much detail as possible:
The instructions really depend on what style tensioner your car has. If you have the hydraulic tensioner that looks like a mini shock absorber, then you only need to replace the tensioner pulley and alternator idler pulley to get rid of the noise. If you have the older style mechanical tensioner (round with a 16mm head sticking out of it) then you'll have to upgrade to the hydraulic style because the mechanical style has been discontinued.
Remove the fan clutch. The best way is to take a long, thin 32mm wrench and smack hard in a downward/right motion with a hammer. Remember the fan is reverse threaded, so go clockwise to loosen it and counterclockwise to tighten it.
Remove the A/C bel firstt. You'll need a 16mm socket. Rotate the tensioner clockwise to release the tension on the belt and pull it off.
Before you remove the alternator belt, get a piece of paper and sketch out the routing of the belt so you don't forget how it goes.
If you have a mechanical alternator belt tensioner, you'll release the tension on the alternator belt the same way as you do with the A/C belt (16mm socket, counterclockwise). To remove the tensioner, first you have to remove the alternator idler pulley (which you should replace) by removing the long 16mm bolt. Next, release the two 13mm bolts on the top and bottom of the belt tensioner.
If you have a hydraulic tensioner, remove the dust cap from the idler pulley and use that bolt head (either torx or hex depending on the car, and I can't remember the exact size). Turn in a clockwise motion to relieve the tension on the belt, and pull it off.
If you're upgrading from mechanical to hydraulic, you'll have to buy the whole kit from the dealership, including all of the bolts. I have listed the part numbers you'll need at the bottom of the post. When you pick it up from the dealership, ask them to print the exploded diagram from the parts catalog, because it will be helpful when you go to assemble and install the new tensioner.
You'll have to bolt the tensioner brackets with the shock on as a unit (3 13mm bolts mount in preexisting holes in the front of the engine
- it should come partially assembled) in the same location as the old tensioner. The pulleys don't go on until after you've bolted the body of the tensioner down. Don't forget the dust cover that goes on back of the tensioner pulley.
Reinstall the belts the same way that you removed them, and make sure that they're lined up properly on the pulleys. Spin your fan back on. Tighten it up and you're done.
I tried to go into as much detail as possible, but without pictures, some of this might not make much sense. If you have questions or need anything clarified, let me know. Here's the list of parts you'll need to upgrade your tensioner:
11 28 1 437 475 Ribbed V-Belt 1
11 28 1 726 774 Base Plate 1
11 28 1 726 773 Pitman Arm 1
11 28 1 748 131 Adjusting Pulley 1
07 11 9 920 150 Fillister Head Screw 1
11 28 1 717 188 Hydraulic Tensioner 1
07 11 9 913 111 Hex Bolt 2
07 11 9 912 652 Hex Bolt 1
07 11 9 901 785 Hex Bolt 1
11 28 1 440 369 Flat Washers 3
07 11 9 932 121 Wave Washers 1
11 28 1 727 159 Protection Cap – Pulley 1
12 31 1 713 143 Protection Cap – Pitman Arm 1
11 28 1 730 532 Mudguard 1