Alternator Belt

This procedure covers the removal and replacement of the serpentine alternator belt on the 5.9L Cummins diesel engine.

Warnings

Tools required

Parts

• Serpentine belt × 1 — Gates K060965 or equivalent for 5.9L Cummins

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine to cool completely if recently operated
3. Verify you have the correct replacement belt by comparing length and width to the old belt
4. Take a photo or sketch of the belt routing path around all pulleys

Procedure

1. 1

   Access the belt tensioner
   Open the hood and locate the serpentine belt on the front of the engine. The automatic belt tensioner is located on the front of the engine on the passenger side, near the top of the accessory drive. Identify the tensioner arm and the bolt/square drive used to rotate it for releasing tension.
2. 2

   Document belt routing
   Verify the belt routing matches the diagram on the fan shroud or upper radiator support. The belt runs around the crankshaft pulley, water pump/fan drive, power steering pump, idler pulley, A/C compressor (if equipped), alternator, and tensioner pulley. Verify the exact routing against the vehicle's diagram, as it varies by accessory configuration. If the diagram is missing or unclear, take a detailed photo from multiple angles.
3. 3

   Release belt tension
   Insert a 1/2" breaker bar or serpentine belt tool into the tensioner arm drive. Rotate the tensioner in the direction that relieves belt tension (verify direction against the tensioner arm travel, typically counterclockwise on the 5.9L Cummins). Maintain steady pressure to keep the tensioner rotated.
   ⚠Do not release the tensioner suddenly as it is under heavy spring tension
4. 4

   Remove the old belt
   While holding the tensioner in the released position, slip the belt off the alternator pulley or any other accessible pulley. Once the belt is loose on one pulley, carefully release the tensioner and remove the belt completely from all pulleys. Route the belt out from the engine compartment.
5. 5

   Inspect pulleys and tensioner
   With the belt removed, spin each pulley by hand to check for roughness, noise, or excessive play. Check the tensioner arm for smooth operation and verify the tensioner pulley spins freely without wobble. Inspect all pulley surfaces for scoring, glazing, or damage that could cause premature belt wear.
6. 6

   Route the new belt
   Starting at the crankshaft pulley at the bottom of the engine, route the new belt around all pulleys EXCEPT the alternator pulley, following the documented routing pattern. Ensure the belt ribs are properly seated in each pulley groove. The belt should run smoothly without twisting or crossing over itself.
7. 7

   Install belt on alternator
   Using the breaker bar, rotate the tensioner again in the tension-relieving direction to create slack. While holding tension, slip the belt onto the alternator pulley, ensuring the ribs are fully seated in the pulley grooves. Carefully and slowly release the tensioner to apply proper tension to the belt.
8. 8

   Verify belt installation
   Visually confirm the belt is properly seated on all pulleys with ribs fully engaged in each groove. Check that the belt is not twisted anywhere along its path. The belt should sit centered on each pulley without riding on the edges. Verify the routing matches your reference photo or the routing diagram.

Reassembly

1. No disassembly of components is required for this procedure

Verification

• Start the engine and listen for any unusual squealing, chirping, or rubbing noises from the belt area
• Observe the belt while the engine idles to ensure it runs smoothly on all pulleys without slipping or vibrating
• Turn the steering wheel lock to lock with engine running to verify the belt does not slip on the power steering pump pulley under load
• Check belt tension by pressing firmly on the belt midway between two pulleys - it should deflect approximately 1/2 inch with firm thumb pressure
• After running the engine for 5 minutes, shut it off and recheck belt alignment on all pulleys

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