GM Full-Size Trucks 1988-1998 Repair Information

Belts

Print

INSPECTION



See Figures 1, 2, 3, 4 and 5

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.



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

ADJUSTMENT



V-Belts

See Figures 6 and 7



Click image to see an enlarged view

Fig. Fig. 6: Common belt tension gauges



Click image to see an enlarged view

Fig. Fig. 7: 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, V8 gasoline engines: used-90 ft. lbs. (122Nm); new-135 ft. lbs. (183 Nm).
     
    6-4.8L: used-90 ft. lbs. (122 Nm); new-169 ft. lbs. (229 Nm).
     
    V8-6.2L/6.5L diesel: used-67 ft. lbs. (90 Nm); new-146 ft. lbs. (197 Nm).
     

  8.  

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

Serpentine Belts

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

REMOVAL & INSTALLATION



V-Belts

See Figures 8, 9 and 10

  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. 8: Push the component toward the engine and slip off the belt



Click image to see an enlarged view

Fig. Fig. 9: Slip the new belt over the pulley



Click image to see an enlarged view

Fig. Fig. 10: Pull outward on the component and tighten the adjusting and mounting bolts

It is better to have belts too loose than too tight, because overtight 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 Belts

See Figure 11

  1. On all models except the 7.4L engine with A.I.R. pump (California emissions only), use a 1 / 2 in. breaker bar with a socket placed on the tensioner pulley bolt, rotate the tensioner to relieve belt tension.
  2.  
  3. On all 7.4L engines with a A.I.R. pump (California emissions only), use a suitable wrench on the pulley axis bolt to rotate the tensioner clockwise to relieve belt tension.
  4.  
  5. Remove the serpentine belt.
  6.  

To install:
  1. Route the belt over all the pulleys except the tensioner.
  2.  
  3. On all models except the 7.4L engine with A.I.R. pump (California emissions only), place the breaker bar and socket on the tensioner pulley bolt and rotate the tensioner to the released position.
  4.  
  5. Install the belt and return the pulley to its original position.
  6.  
  7. On all 7.4L engines with a A.I.R. pump (California emissions only), use a suitable wrench on the pulley axis bolt to rotate the tensioner clockwise to relieve belt tension.
  8.  
  9. Install the belt and return the pulley to its original position.
  10.  
  11. Check that the belt is properly seated in each pulley.
  12.  



Click image to see an enlarged view

Fig. Fig. 11: Rotate the tensioner with a breaker bar to relieve belt tension

BELT ROUTING



See Figures 12 through 31



Click image to see an enlarged view

Fig. Fig. 12: Drive belt routing-1988-90 5.7L HD engines



Click image to see an enlarged view

Fig. Fig. 13: Drive belt routing-1988-90 5.7L, 6.2L engines



Click image to see an enlarged view

Fig. Fig. 14: Drive belt routing-1988-90 4.3L, 5.0L and 7.4L engines



Click image to see an enlarged view

Fig. Fig. 15: Drive belt routing-1991 5.7L engines, R/V series



Click image to see an enlarged view

Fig. Fig. 16: Drive belt routing-1991 6.2L engines, R/V series



Click image to see an enlarged view

Fig. Fig. 17: Drive belt routing-1991 6.2L HD, 4.3L engines



Click image to see an enlarged view

Fig. Fig. 18: Drive belt routing-1991 7.4L engines, R/V series



Click image to see an enlarged view

Fig. Fig. 19: Drive belt routing-1991 4.3L, 5,0L, 5.7L and 6.2L engines, C/K series



Click image to see an enlarged view

Fig. Fig. 20: Drive belt routing-1991 7.4L engines, C/K series



Click image to see an enlarged view

Fig. Fig. 21: Drive belt routing-1992-93 4.3L, 5.0L and 5.7L engines w/o AC



Click image to see an enlarged view

Fig. Fig. 22: Drive belt routing-1992-93 4.3L and 5.7L engines w/AC



Click image to see an enlarged view

Fig. Fig. 23: Drive belt routing-1992-93 7.4L engines



Click image to see an enlarged view

Fig. Fig. 24: Drive belt routing-1992-93 6.2L and 6.5L engines



Click image to see an enlarged view

Fig. Fig. 25: Drive belt routing-1994-95 4.3L, 5.0L and 5.7L engines, C/K series (without A.I.R.)



Click image to see an enlarged view

Fig. Fig. 26: Drive belt routing-1994-95 4.3L, 5.0L and 5.7L engines, C/K series (with A.I.R.)



Click image to see an enlarged view

Fig. Fig. 27: Drive belt routing-1994-95 7.4L engines, C1, C/K 2,3 series



Click image to see an enlarged view

Fig. Fig. 28: Drive belt routing-1994-95 Diesel engines



Click image to see an enlarged view

Fig. Fig. 29: Drive belt routing-1996-98 4.3L, 5.0L and 5.7L engines



Click image to see an enlarged view

Fig. Fig. 30: Drive belt routing-1996-98 7.4L engines C/K series



Click image to see an enlarged view

Fig. Fig. 31: Drive belt routing-1996-98 diesel engines

 
label.common.footer.alt.autozoneLogo