What does a serpentine belt operate and do all the pulleys suppose to work 1995 winstar

You need to use a wrench or serpentine belt tool to turn the belt tensioner by connecting to the pulley bolt and turning it clockwise.

draw a diagram first of how it goes around the pulleys.make sure its accurate,and each pulley is named,ie aircon,geni,p/steer/crank/,then usually just need to detension belt by backing off the belt tensioner[use good size spanner or fixed socket on bar]slip belt off.the tensioner usually just springs back,fit new belt reverse way,check against diagram before starting

bent pulley or a bad bearing
belt stretched out of line
oil on the pulley(s)

Click on the following direct Link. It has several Serpentine Diagrams; one of which matches your specific engine and options (ex: AC/No AC etc).
Regarding HOW:
Standard Rule to Removal the Serpentine Belt:
1. Find the Tensioner(s). (See Diagrams on Link)
2. Using a Serpentine Belt Tensioner Tool, Or Wrench OR Ratchet, Rotate/Move the Tensioner USING THE AVAILABLE NUT OR OPENING (3/8ths or 1/2 inch square opening) away from contact with the belt and towards the area where the belt is not in contact with the Tensioner Pulley. The Tensioner is spring loaded, and is hard to rotate/move.
3. Remove the loosened belt off one of the other more easily accessed Pulleys.
Standard Rules for Installing the Serpentine Belt:
a. Pick a Pulley that is most easily accessed. This will usually be on top. This will be the last Pulley that the belt will go on.
b. Using the Diagram: Install the new Serpentine Belt on the remainder of the Pulleys....over, under, left right.
c. Using a Serpentine Belt Tensioner Tool or Wrench or Ratchet Tool: Rotate/Move the Tensioner Pulley/Arm "away" from Belt contact area on the Tensioner. This spring is pretty hard and with a new belt, it will be even harder to install. Rotate/Move this to as-close to the maximum allowed inorder to have enough slack in the belt to get it up and over the last pulley.
d. Using your other hand - Pull the Belt up and over the Last remaining Pulley.
e. Before releasing the pressure on the Tensioner, visually inspect the remainder Pulleys and the Belts' Positioning on them.
Let me know if this helped...
http://www.2carpros.com/car_repair_information/year/1995/make/chevrolet/model/caprice/1995_chevrolet_caprice_drive_belt_routing_diagram.htm

Use a 6 or 8 inch 1/2 socket extension bar and place it in the top of the tensioner pulley, there is a notch in pulley for this. The tensioner pulley is near the firewall at the top of the engine....make a diagram of the belt routing and note which side( smooth or grooved) is lying on the pulley(usually grooved side of belt). Next you would pull tensioner pulley forward and slip the old belt off....you would route your new belt the same way and slip it on the tensioner pulley last.....you will need to pull the tensioner pulley forward again to get the slack you need to slide the belt over the pulley. I have found the Saab to be one of the easiest cars to change the serpentine belt on. I hope this helps.

e



Fig. Accessory drive belt routing-3.0L engine




Fig. Accessory serpentine belt routing-3.0L engine




Fig. Accessory serpentine belt routing-3.8L engine


Removal and Installation



Fig. Drive belt tensioner wear indicator marks




Fig. Place a wrench on the drive belt tensioner bolt and rotate the assembly clockwise to relieve belt tension

Using a 15mm wrench attached to the drive belt tensioner pulley, rotate the tensioner clockwise to release the tension. Remove the drive belt from the pulley. When installing the new drive belt, ensure that the drive belt is routed correctly and note the position of the indicator mark on the tensioner.

Hope heled with this; remember rated this help. Good luck.

1.Either you do not have the belt lined up correctly with the grooves on the pulleys,

2.Or the belt has not been installed in the correct pattern,

3.Or your belt tensioner pulley has a weak or broken spring, and is not pushing against the belt.
I found this problem on a car recently.
The tensioner pulley that you are supposed to pull back on, has to push against the belt. It also has to push with enough force.

use a 15mm socket to loosen the tensioner,the bolt isnt supposed to come out but the tensioner turns,turn it enough to pull the belt off the alternator then there is enough slack to work with it.

The A/C pully is supposed to spin freely until the AC is activated to run.. The cranshaft pully does not. Replace the tensioner pully. The belt has to fit in between the grooves on the pullys.

There is a Large Pulley above the Tensioners Small Pulley. This Larger Pulley has a Bolt in the Middle of it. Geta Socket and Wratchet and Tork this Bolt and it will Lower the Tensioner so that you can Reinstall it.