I assume you mean the idler pulley on the A/C belt. I have not replaced this particular item but it should be simple.
Looking from the top of the engine compartment on the passenger side you will see the idler pulley with a mounting/locking bolt which attaches the pulley and the tension adjusting point immediately above it. Loosen the pulley locking bolt by turning counter clockwise. Relieve belt tension by turning the adjuster bolt counter clockwise. Remove the belt and pulley. Replace in the reverse order.
Typically, there is one pulley that is mounted on a spring arm to maintain proper belt tension. Just turn the bolt on the idler pulley and the tensioner will release.
Which pulley?
It depends on which pulley. Locate the problem one and replace it. It may be the water pump or alternater in which case those components need replacement. Also may be the idler pulley is bad.
Left Hand. Size 50 Torx
alternator-,ac pump-,steering pump-,crank pully-, idler pulley-,water pump
you have to do this from under the van. jack the vechicle up and be sure to support it on jack stands for `safety. right behind the pulley ia a 15 mm bolt this bolt is the only bolty that holds the pully on. it is harde to get to a person with small hand has little or less problems.
Having the engine type is crucial here, but if it is a 4.0 just loosen the idler pulley bolt, then turn the idler pulley adjuster counter clockwise until sufficient slack is in the belt, remove it ans place the new one on as the diagram shows on your radiator bracket right near the hood latch.
The idler pulley is near the top of the engine. Use a 15 MM (I think) socket on a long breaker bar, and turn the idler pulley arm so that the pulley moves away from the belt. You'll need to put the socket on the nut of the pulley, not on the arm itself. When the pulley is loose, you can pull the belt off. Some of the idler pulley arms have a square hole that accepts a 1/2 inch drive from a socket wrench breaker bar. But be careful. The serpentine belt routing is a little odd, and you'll want a picture to help you put it back. Make a drawing or take some pictures if you don't already have something from GM.
This is an extremely eays job and takes just a couple minutes. you need a n apropriate size socket a short extension and a rachet. loosen the bolt through the pulley and remove it and the pulley replace in reverse order. The pully is at the top of the engine, in front and just left of center. This job is easier than replacing sparkplugs.
What you need is a ratchet 15mm socket. Losen the idler then slide off the serpentine belt off. There should be a diagram for routing the belt if not draw a diagram before removing it. Replace the serpentine belt crank it 2 or 3 times but don't start the engine. The 4th time start the engine this time the as the engine is idling eyeball the belt agaisnt the tensioner idler and crank pulley make sure the serpentine is algined. A Note: Make sure that you have identified the tensioner pulley as apposed to the idler pulley. With the 15mm socket on the tensioner pulley's bolt, rotate it clockwise and this will release the tension on the belt, or in the case of installing a new serpentine belt, allow you to get it where it belongs. This is the case on my 1997 Dodge Caravan, and probably other year makes. Best of luck- Bryan 1993 Dodge Grand Caravan: Rotating the tensioner pulley's bolt clockwise was the way to replace my belt. By the way, the tensioner pulley in my van was one of the smaller ones in the middle of the whole system, attached to a silver arm coming off the tensioner. Good luck...
NISSAN MADE 2 DIFFERENT MOTORS STARTING IN 92 LOOK ON THE FIREWALL AND FIND A LITTLE ALUMINIUM PLATE IT WILL TELL YOU IF IT IS A VG30E OR A VG30DE THIS WILL MAKE A DIFFERANCE IN IDLER PULLEY AJUSTMENT.THE CHILTONS MANUAL IS THE BETTER MANUAL TO HAVE FOR LOCATING THE TENTION RELIESE BOLT ON THE IDLER PULLEY CHAPTER 1 # 19 . LOOK IN YOUR LOCAL LIBRARY FOR A COPY OF THE MANUAL AND PHOTOCOPY THIS PAGE.ITS NOT A HARD OR LONG JOB BUT YOU HAVE TO RELIESE THE TENTION ON THE BELT THEN REPLACE AND RETIGHTEN THE BELT...............HOPE THIS HELPS...BUDDY MACK
Try tightening the mounting bolt on the idler and/or tensioning pullies. This did the trick for a persistent squeek on my 93' Jeep Wrangler. On some cars, the idler pulley {usually on the belt tensioner) can squeal. If you squirt some WD-40 or similar lubricant on the front of the bearing (engine off), and the noise goes away, it is probably the bearings in the idler pulley. If this is the case, replace the idler pulley, because the noise will come back after the lubricant gets slung out of the bearing. I also have a Plymouth laser, I had the same problem and tryed the same things. If the above answers don't seem to work, look at the water pump. In the water pump there are ball bearings the keep it spinning smoothly and when the casing of the bearings give way, the bearings no longer glide over the surface, instead they bunch up and rub against the back of the pulley. If this is the case, you will be able to see the bearings behind the pulley.