Cummins ISX11.9 CM2250 – Service Manual 008-002   Drive Belt, Cooling Fan

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Disconnect the batteries. Refer to the OEM service manual.

Due to the number of cooling fan drive belt arrangements, this procedure does not cover all available cooling fan drive belt routings.

To be sure the cooling fan drive belt is routed correctly upon installation, make a diagram of the cooling fan belt routing, as shown in the illustration, prior to removing the belt.

The cooling fan belt routing typically consists of the following components, but may not include all of them:

1. Crankshaft pulley/vibration damper
2. Fan pulley
3. Water pump pulley
4. Alternator pulley
5. Idler pulley(s)
6. Belt tensioner pulley.

CAUTION  The belt tensioner is spring loaded and must be pivoted away from the drive belt. Pivoting in the wrong direction can result in damage to the belt tensioner or cause personal injury.

The belt tensioner winds in the direction that the spring tang is bent over the tensioner body. To loosen the tension on the belt, rotate the tensioner to wind the spring tighter.

CAUTION  Applying excessive force in the opposite direction of windup or after the tensioner has been wound up to the positive stop can cause the tensioner arm to crack or break.

Make a diagram of the belt arrangement prior to removing the drive belt to aid in installation and provide proper routing of the cooling fan drive belt.

Pivot the tensioner in the direction of the spring tang (clockwise) to remove the drive belt.

Remove the drive belt.

Check the belt for damage. Transverse (across the belt width) cracks are acceptable. Longitudinal (direction of the belt length) cracks that intersect with transverse cracks are not acceptable. If the belt is frayed or has any piece of material missing, the belt is unacceptable and needs to be replaced.

Inspect the belt for:

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

Replace the belt if any damage is found.

NOTE: If a damaged belt has spun on a pulley, inspect the pulley and assembly for damage. Refer to Procedure 008-089 in Section 8.

Inspect the idler and drive pulleys for wear or cracks.

Clean, check, and reuse idlers with a buildup of dirt, rather than replacing them. Refer to Procedure 008-089 in Section 8.

Inspect the belt tensioner. Refer to Procedure 008-087 in Section 8.

Inspect the pulley alignment.

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

CAUTION  The belt tensioner is spring loaded and must be pivoted away from the drive belt. Pivoting in the wrong direction can result in damage to the belt tensioner or cause personal injury.

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.

Route the drive belt on the engine using the belt diagram created in the remove step.

Install a new fan belt on the pulleys.

Pivot the tensioner in the direction of the spring tang (clockwise) and install the drive belt, slipping the belt over the water pump pulley last.

Release the tensioner to apply tension to the drive belt.

Check the alignment of the belt with the tensioner and the rest of the front end auxiliary drive.

Inspect the pulley alignment.

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

WARNING  Batteries can emit explosive gases. To reduce the possibility of personal injury, always ventilate the compartment before servicing the batteries. To reduce the possibility of arcing, remove the negative (-) battery cable first and attach the negative (-) battery cable last.

• Connect the batteries. Refer to the OEM service manual.
• Operate the engine and check for belt squeal. Excessive belt squeal indicates belt slippage.
• If belt squeal is present, check the routing of the belt and make sure that the belt is installed correctly on each pulley.