Serpentine Belt Tensioner

Easy job on those vehicles. Usually need a wrench that fits over the belt tensioner, and you raise or lower it, taking tension off the belt. then just slip it off the nearest pulley-often the alternator pulley. Now you can let go of the tensioner and remove belt. Notice how it is fit. There should be a diagram on a sticker of how the belt fits on.

How To replace Install Engine Serpentine Belt 1996 99 Buick Lesabre 3... How To replace Install Serpentine Belt tensioner 1996 98 Buick Lesabre...

These two videos will help you get the job done. Good Luck !!!

Possibly the tensioner pulley is worn out and needs replaced. It should have wear limit marks on it, a maximum and minimum marking- the tensioner mark should fall between them.

Those belts have a tensioner on them. IF the belt is too big then the tensioner might not be retracted. It might be missing. There are idler pulleys too. If you have high miles on the this car, the pulley or the tensioner might be worn. The tensioner also has to be pulled back to have the belt put on.

Click on the following free direct Link. It has several of the Serpentine Belt Diagrams and Tensioners that are possible with your 2.0L 4-Cylinder engine and engine options (AC/No AC, etc.).

http://www.2carpros.com/car_repair_information/year/1990/make/pontiac/model/sunbird/1990_pontiac_sunbird_drive_belt_routing_diagram.htm

A. Remove the Serpentine Belt.
"HOW TO":
Standard Rules to Removal the Serpentine Belt with a Tensioner:
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 (on the Pulley or Arm Base) OR the OPENING (3/8ths or 1/2 inch square opening) rotating the Tensioner Pulley/Arm - moving it 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.
4. DO NOT quickly release the Tensioner, but gently allow the Tensioner to rest in its closed position.

B. Remove the Tensioner:
Removing the Tensioner Pulley: See the Diagrams in the Link.
After the Belt has been removed, with the Tensioner resting:
DEPENDING ON WHAT TYPE TENSIONER:
(1.) IF the Tensioner Pulley itself HAS a Bolt Head showing, SOME of these bolts can be removed and the Tensioner Pulley replaced.
(2.) IF the Tensioner Pulley itself DOES NOT HAVE a Bolt Head showing, then go to the Tensioner Base located at the end of the Tensioner Arm. This should have a Bolt Head Showing. Remove this Bolt and the whole Tensioner Assembly will come off.
(3.) Some Tensioner Assembly's need you to locate and remove mounting bolts.

If Applicable: When replacing the Tensioner Assembly - MAKE SURE you place the protruding "nipple" on the underside base of the Tensioner into the appropriate cavity on the engine face.

Standard Rules for Installing the Serpentine Belt with Tensioners:
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, or if you have additional information or questions. Feel Free to contact me at FixYa.Com!

1. Remove the belt guard or coolant recovery reservoir as required.
   
2. For 1996-99 supercharged engines, perform the following:
   
   1. Raise and safely support the vehicle.
      
   2. Remove the right-hand splash shield.
      
   3. Remove the connector from the crank sensor.
      
3. For 1996-99 vehicles, remove the engine mounting bracket lower nut, stud and spacer. Carefully lower the vehicle.
   

CAUTION To avoid personal injury when rotating the serpentine belt tensioner, use a tight fitting wrench that is at least 24 in. (61cm) long.

1. Take note of the belt's routing. Lift or rotate the tensioner using a suitable sized breaker bar in the square opening or box end wrench on the pulley nut. Remove the belt from the pulleys.
   

You can use a box-end wrench on the pulley nut to rotate the tensioner ...


... then remove the belt from the pulleys

Your '90 Benz has a belt tensioner that is automatic. You just insert the correct tool to ease the tensioner pulley, (The tool is inserted into the bracket for the tensioner pulley), to the left as you're facing the car. Then slip your serpentine belt off. Reinstallation is a reversal of this process. (I believe it's to the left, don't quote me on that)

The radiator support in front, should have a diagram of how the serpentine belt goes on the pulleys.

If your serpentine belt slips, then the belt tensioner pulley assembly is bad, needs to be replaced, or the serpentine belt itself is worn out.

There a few different layouts for that car year and model so here is a link and you will find what you need .. Thanks for using FixYa and please rate me a FixYa .. Crayz

the "serp" belt is self-adjusted by a spring loaded tensioner pulley. the proper size wrench or a 3/8" square drive inserted in the tensioner and rotated will release the tension to allow the belt to come off. reverse order to install. DRAW A PICTURE OF THE ROUTING OF THE BELT AROUND THE PULLEYS BEFORE REMOVING CURRENT BELT!!

One pulley is a tensioner. Put a wrench on the nut in the center of the pulley and relieve the tension from the belt.