ISM, ISMe, and QSM11 – 008-002   Drive Belt, Cooling Fan

NOTE: Consult the vehicle manufacturer for fan hub installations that were not supplied by Cummins Inc.

Do not adjust belt tension to full value with the adjusting screw. Belt tension can increase when the locknut is tightened and cause reduced belt and bearing life.

Loosen the idler pulley shaft locknut.

Use belt tension gauge, Part Number ST-1293 or equivalent, and the belt tension chart to adjust the belt to the correct tension. Refer to Procedure 018-005 in Section V.

Tighten the idler pulley shaft locknut.

Check the belt tension again to make sure the belt is not too tight.

Loosen the fan idler pulley shaft locknut.

Turn the adjusting screw counterclockwise to release the belt tension.

Move the fan idler pulley and fan pulley centers as close as possible. The belt can then be removed without excessive force.

Inspect the belt for:

• Cracks
• Glazing
• Tears or cuts
• Excessive wear.

Inspect the pulley alignment.

Pulley misalignment must not exceed 6 mm [0.236 in] for each meter [39.4 in] 1.6 mm for each 305 mm [1/16 inch for each 12 inches] of distance between the pulley centers.

Replace the fan idler pulley and fan hub pulley if they are not in alignment. Refer to Procedure 008-030 in Section 8.

CAUTION  To reduce the possibility of damage to the pulley and new belt, do not roll the belt over the pulley or pry it on with a tool.

Install a new fan belt on the pulleys.

Use belt tension gauge, Part Number ST-1293, or equivalent, to measure the belt tension. Refer to Procedure 018-005 in Section V.

Turn the adjusting screw to adjust the belt tension.

NOTE: A belt is considered used if it has been in operation 10 minutes or longer. If used belt tension is below the minimum value, tighten the belt to the maximum value. Replace the belt if it will not maintain correct tension.

Tighten the idler pulley shaft locknut.

Check the belt tension again to make sure belt is not too tight.

Inspect for pulley misalignment. It must not exceed 6 mm [0.236 in] for each meter [39.4 in] 1.6 mm for each 305 mm [1/16 inch for each 12 inches] of distance between the pulley centers.

Replace the fan idler pulley and fan hub pulley if they are not in alignment.Refer to Procedure 008-030 in Section 8.