GM Full Size Vans 1987-1997 Repair Guide

Belts

Print

INSPECTION



See Figures 1 through 7

Inspect the belts for signs of glazing or cracking. A glazed belt will be perfectly smooth from slippage, while a good belt will have a slight texture of fabric visible. Cracks will usually start at the inner edge of the belt and run outward. All worn or damaged drive belts should be replaced immediately. It is best to replace all drive belts at one time, as a preventive maintenance measure, during this service operation.

Newer models have certain components driven by a serpentine belt. Serpentine belts are automatically tensioned by a system of idler and tensioner pulleys, and thus, require no adjustment.



Click image to see an enlarged view

Fig. Fig. 1: There are typically 3 types of accessory drive belts found on vehicles today



Click image to see an enlarged view

Fig. Fig. 2: An example of a healthy drive belt



Click image to see an enlarged view

Fig. Fig. 3: Deep cracks in this belt will cause flex, building up heat that will eventually lead to belt failure



Click image to see an enlarged view

Fig. Fig. 4: The cover of this belt is worn, exposing the critical reinforcing cords to excessive wear



Click image to see an enlarged view

Fig. Fig. 5: Installing too wide a belt can result in serious belt wear and/or breakage



Click image to see an enlarged view

Fig. Fig. 6: V-belts should ride slightly above the pulley



Click image to see an enlarged view

Fig. Fig. 7: On serpentine belts, the ribs of the belt should be positioned in the pulley grooves as shown

V-Belts

See Figures 8 and 9



Click image to see an enlarged view

Fig. Fig. 8: Common belt tension gauges



Click image to see an enlarged view

Fig. Fig. 9: Measuring belt deflection

Belt tension should be checked with a gauge made for the purpose. If a tension gauge is not available, tension can be checked with moderate thumb pressure applied to the belt at its longest span midway between pulleys. If the belt has a free span less than 12 in. (305mm), it should deflect approximately 1 / 8 - 1 / 4 in. (3-6mm). If the span is longer than 12 in. (305mm), deflection can range between 1 / 8 in. (3mm) and 3 / 8 in. (9.5mm).

If a tension gauge is available use the following procedure:

  1. Place a belt tension gauge at the center of the greatest span of a warm (not hot) drive belt and measure the tension.
  2.  
  3. If the belt is not within the specification, loosen the component mounting bracket and adjust to specification.
  4.  
  5. Run the engine at idle for 15 minutes to allow the belt to reseat itself in the pulleys.
  6.  
  7. Allow the drive belt to cool and re-measure the tension. Adjust as necessary to meet the following specifications:

    V6 and V8 gasoline engines: used belt - 90 ft. lbs. (122 Nm); new belt - 135 ft. lbs. (183 Nm).
     
    6.2L and 6.5L diesel engines: used belt - 67 ft. lbs. (90 Nm); new belt - 146 ft. lbs. (197 Nm).
     

  8.  

A belt is considered "used" after 15 minutes of operation.

Serpentine Drive Belts

The serpentine belt tension can be checked by simply observing the belt's acceptable wear range indicator, located on the tensioner spindle. If the belt does not meet the specification, it must be replaced.

DRIVE BELT ROUTING



See Figures 10 through 35



Click image to see an enlarged view

Fig. Fig. 10: The drive belt routing schematic is usually found on a label in the engine compartment

A label is normally provided in the engine compartment which details the proper belt routing for the original engine installed in the vehicle. Check the routing label (or vehicle emission control label) for an illustration which resembles your engine first. If no label is present or if the label does not match your engine, refer to the routing diagrams found in this section. In cases where engine swaps were made, determine the year or the engine using your codes, or visually match the accessories to the diagrams provided.



Click image to see an enlarged view

Fig. Fig. 11: Serpentine drive belt routing - 1987-92 4.3L, 5.0L, 5.7L and 7.4L engines (G models)



Click image to see an enlarged view

Fig. Fig. 12: Drive belt routing - 1987-92 5.7L and 6.2L engines (G models)



Click image to see an enlarged view

Fig. Fig. 13: Drive belt routing - 1987-92 5.7L engine with heavy duty emissions (G models)



Click image to see an enlarged view

Fig. Fig. 14: Drive belt routing - 1987-92 7.4L engine (P models)



Click image to see an enlarged view

Fig. Fig. 15: Drive belt routing - 1987-92 5.7L engine with heavy duty emissions (P models)



Click image to see an enlarged view

Fig. Fig. 16: Drive belt routing - 1987-92 4.3L and 5.0L engines (P models)



Click image to see an enlarged view

Fig. Fig. 17: Serpentine drive belt routing - 1993-95 7.4L engines (G models)



Click image to see an enlarged view

Fig. Fig. 18: Drive belt routing - 1993-95 diesel engines (G models)



Click image to see an enlarged view

Fig. Fig. 19: Serpentine drive belt routing - 1993-95 4.3L, 5.0L and 5.7L engines (G models)



Click image to see an enlarged view

Fig. Fig. 20: Drive belt routing - 1993-95 4.3L engine (P models)



Click image to see an enlarged view

Fig. Fig. 21: Drive belt routing - 1993-95 5.7L engines (P models)



Click image to see an enlarged view

Fig. Fig. 22: Drive belt routing - 1993-95 7.4L engine (P models)



Click image to see an enlarged view

Fig. Fig. 23: Serpentine drive belt routing - 1993-95 6.5L engine (P models)



Click image to see an enlarged view

Fig. Fig. 24: Serpentine drive belt routing - 1996-97 4.3L, 5.0L and 5.7L engines with A/C (G models)



Click image to see an enlarged view

Fig. Fig. 25: Serpentine drive belt routing - 1996-97 4.3L, 5.0L and 5.7L engines without A/C (G models)



Click image to see an enlarged view

Fig. Fig. 26: Serpentine drive belt routing - 1996-97 7.4L engine without A/C (G models)



Click image to see an enlarged view

Fig. Fig. 27: Serpentine drive belt routing - 1996-97 7.4L engine with air pump, but no A/C (G models)



Click image to see an enlarged view

Fig. Fig. 28: Serpentine drive belt routing - 1996-97 ambulance with 6.5L engine (G models)



Click image to see an enlarged view

Fig. Fig. 29: Serpentine drive belt routing - 1996-97 6.5L diesel engine (G models)



Click image to see an enlarged view

Fig. Fig. 30: Serpentine drive belt routing - 1996-97 7.4L engine with A/C (G models)



Click image to see an enlarged view

Fig. Fig. 31: Serpentine drive belt routing - 1996-97 7.4L engine with air pump and A/C (G models)



Click image to see an enlarged view

Fig. Fig. 32: Drive belt routing - 1996-97 5.7L engine (P models)



Click image to see an enlarged view

Fig. Fig. 33: Drive belt routing - 1996-97 diesel engines (P models)



Click image to see an enlarged view

Fig. Fig. 34: Drive belt routing - 1996-97 4.3L engine (P models)



Click image to see an enlarged view

Fig. Fig. 35: Drive belt routing - 1996-97 7.4L engine (P models)

REMOVAL & INSTALLATION



V-Belts

See Figures 36 through 39

  1. Loosen the driven accessory's pivot and mounting bolts. Remove the belt.
  2.  
  3. Install the belt. Move the accessory toward or away from the engine until the tension is correct. You can use a wooden hammer handle, or broomstick, as a lever, but do not use anything metallic, such as a prybar. Certain models may utilize an adjusting bolt to do this work for you. Simply loosen the mounting bolt and turn the adjuster!
  4.  
  5. Tighten the bolts and recheck the tension. If new belts have been installed, run the engine for a few minutes, then recheck and readjust as necessary.
  6.  



Click image to see an enlarged view

Fig. Fig. 36: Push the component toward the engine and slip off the belt



Click image to see an enlarged view

Fig. Fig. 37: Slip the new belt over the pulley



Click image to see an enlarged view

Fig. Fig. 38: Pull outward on the component and tighten the adjusting and mounting bolts

It is better to have belts too loose than too tight, because overtightened belts will lead to bearing failure, particularly in the water pump and alternator. However, loose belts place an extremely high impact load on the driven component due to the whipping action of the belt.

Serpentine Drive Belts
  1. For safety purposes, disconnect the negative battery cable.
  2.  

It may be necessary to remove the air filter housing to gain access to the belt tensioner.

  1. If necessary, remove the air filter housing cover and filter as outlined in this section.
  2.  
  3. Tag and disconnect the hoses and loosen the housing retainers. Remove the housing from the engine compartment.
  4.  
  5. Using a 1 / 2 in. breaker bar with a socket placed on the tensioner pulley bolt, rotate the tensioner to relieve belt tension.
  6.  
  7. Remove the serpentine belt.
  8.  

To install:
  1. Route the belt over all the pulleys except the tensioner.
  2.  
  3. Place the breaker bar and socket on the tensioner pulley bolt and rotate the tensioner to the released position.
  4.  
  5. Install the air cleaner housing and tighten the retainers.
  6.  
  7. Install the air filter element and housing cover.
  8.  
  9. Connect the negative battery cable.
  10.  
  11. Install the belt and return the pulley to its original position.
  12.  
  13. Check that the belt is properly seated in each pulley.
  14.  



Click image to see an enlarged view

Fig. Fig. 39: Rotate the tensioner with a breaker bar to relieve belt tension

 
label.common.footer.alt.autozoneLogo