I don't know if your 96 is the same as mine, but I just did this job on a 95 Corsica with 3.1 V6. On mine, I had to lower the engine to get at the bolt holding the tensioner on the engine.
Required tools:
(I used 15mm open ended wrench)
all the way up to 15 mmm engine mounting bolts.
1. Set rear brake and chock rear tires
2. Loosen lug nuts on passenger side front tire.
3. Lift and support front of car on jack stands. I recommend placing them beneath front tires, under the jack notches, at the lowest heights.
4. Remove tire and mud guard(s) to expose the lower pulley assembly. You should be able to see the front crank shaft pulley wheel with the tensioner assembly located to the left.
5. Loosen the serpentine belt and slip it off of the alternator. Leave the belt on the car unless it absolutely needs replacement (A separate job that possibly requires removing a different set of bolts and mounts than what is described in step 9).
6. Use hydraulic service jack with sufficient lift (despite the fact that the car is already on jacks) and support to reach the oil pan, raise the engine 1-2 inches, and, most importantly, support the engine while you lower it in step 10. I used a $70 3-ton service jack from Wal-Mart. Anything lighter and cheaper probably won't work.
7. Place plywood between the jack head and the oil pan and raise the engine 1-2 inches in order to relieve pressure of engine mounting bolts.
8. Wedge a wood 2x4 (approx. 2' long) behind the alternater. This will allow better access to the tensioner bolt by keeping the engine from rolling towards the firewall during step 10, and it can be used as a pry bar to help realine the these bolt holes during reassembly.
9. Remove the three 15 mm bolts from the engine mounting bracket closest to the pulley assembly. On mine car there were two in back and one in front.
10. Slowly unscrew service jack handle and watch the passenger side of the engine lower. Let it down very slowley until you can see/get to the tensioner bolt. Retighten the jack handle. If you are not going to block the engine at this heigth and will only rely upon the jack to hold the engine while you replace the tensioner, DO NOT GET UNDER THE ENGINE FOR ANY REASON (you should not need to anyway).
11. You should now be able to see the tensioner bolt. I used standard socket with ratchet and 4" extender. If angle is extreme, you might need to use a swivle. Also, you might also need to unclip the coolant hose from its fender brackets and lower it or pull it back to improve access the the bolt.
12. Remove and replace tensioner.
13. Reroute serpentine belt around the tensioner and all other other pulleys except for the alternator.
14. Do reverse of steps 10 - 1. JOB COMPLETE.
on a 96 (3.1 V6) it's a side mount it is on the passenger side of the car on the side of the engine, very close to the fender. the tensioner wheel will accept either an open end wrench or a 1/2 inch or larger pull bar. You will need a pull bar to change the tensioner or the belt, you can rent them from many autoparts stores.
Use a 15mm closed end wrench on the tensioner pulley bolt and rotate the tensioner arm away from the drive belt. Remove the old belt and release the tensioner slowly so that it will not snap back and ruin it.
Usualy the tensioner or idler pulley is spring loaded and can be pulled backwards allowing enough slack for the belt to slip on easily On a 1992-1996 Beretta/Corsica, the upper engine mount needs to be removed in order to remove/replace the serpentine belt. Replace the belt, and reinstall the engine mount.
If you're certain that the sound is from the serpentine belt you should check the belt tensioner. A weak tensioner spring will result in slipping and a noisy belt.
All you need is a ratchet that fits in the square hole where the belt tensioner is. Move it one way to slack the tensioner.
wiring order tune up
I'm assuming that you already have the serpentine belt off. its the smooth pulle, and bracket. located the pulley, and on either side there should be a bolt remove the bolts and pull off. steer the wheel to the right. for a better veiew.look under the panel, locate the tensioner it has a screw in the middle. you probably need a wrench.
the only belt with a tensioner is the timing belt, to tighten the alt belt loosen the adjustment bolt then tap the alt back then retighten the bolt
remove belt via tensioner, four bolts on pulley, five on pump, clean and reverse
Use a 3/8 drive rachet to push down on the belt tentioner it goes right in the tensioner,,While holding it down remove the serpentine belt.
Note:The drivebelt routing decal on the radiator shroud to help during drivebelt install * To replace the belt rotate the tensioner pulley clockwise to release belt tension * Remove the belt from the auxiliary components and slowly release the tensioner * Route the new belt over the various pulleys again rotating the tensioner to allow the belt to be installed then release the belt tensioner
Note:The drivebelt routing decal on the radiator shroud to help during drivebelt install * To replace the belt rotate the tensioner pulley clockwise to release belt tension * Remove the belt from the auxiliary components and slowly release the tensioner * Route the new belt over the various pulleys again rotating the tensioner to allow the belt to be installed then release the belt tensioner