Cooling Fan Clutch

This procedure covers the removal and replacement of the viscous cooling fan clutch on a 2007 Ram 3500 with the 5.9L Cummins diesel engine.

Warnings

Tools required

Parts

• Viscous fan clutch assembly × 1 — Use OEM specification for proper cooling performance
• Fan shroud clips (if damaged) × 4 — OEM replacement clips

Preparation

1. Ensure engine is completely cold to the touch
2. Disconnect negative battery cable to prevent accidental fan engagement
3. Remove the engine cover if equipped to improve access
4. Place towels or cardboard on the radiator to protect it from tools

Procedure

1. 1

   Remove upper fan shroud
   Locate the upper fan shroud mounting clips and fasteners. Remove the two 10mm bolts securing the upper shroud to the radiator support. Release the lower shroud clips by gently prying them with a flathead screwdriver. Carefully lift the upper shroud up and away from the fan assembly, tilting it back toward the engine if needed for clearance.
2. 2

   Access the fan clutch nut
   With the shroud moved back, you now have access to the fan clutch assembly. Locate the wrench flats on the fan clutch where it threads onto the water pump hub. Verify the correct wrench size against the service manual before applying force. Note the thread direction of the fan clutch. On the 5.9L Cummins the fan clutch uses standard RIGHT-HAND threads onto the water pump hub.
3. 3

   Secure the water pump pulley
   Hold the water pump pulley stationary using a fan clutch holding tool or strap wrench wrapped around the pulley. The pulley must be prevented from rotating to break the fan clutch loose. Position the holding tool to brace against a solid engine component or have an assistant hold it firmly.
4. 4

   Loosen the fan clutch
   Using the correct fan clutch wrench, turn the fan clutch nut COUNTERCLOCKWISE to loosen (standard right-hand threads). The initial break may require significant force. Once loose, continue turning counterclockwise by hand until the fan clutch is completely unthreaded from the water pump shaft.
5. 5

   Remove fan and clutch assembly
   Carefully lift the fan and clutch assembly straight up and out of the engine bay. Maneuver it past the radiator and shroud, taking care not to strike the radiator fins or bend the fan blades. Set the assembly on a clean work surface with the fan facing up to prevent damage.
6. 6

   Inspect components
   Examine the old fan clutch for leaking silicone fluid (visible streaks or wetness), play in the bearing, or rough rotation. Check the fan blades for cracks or damage. Inspect the water pump shaft threads for damage. Verify the new fan clutch matches the old unit in mounting pattern and thread direction.
7. 7

   Install new fan clutch assembly
   Thread the new fan clutch assembly onto the water pump shaft by turning CLOCKWISE by hand (standard right-hand threads). Ensure it threads on smoothly without cross-threading. Thread it down until hand-tight against the hub.
8. 8

   Tighten fan clutch
   Hold the water pump hub with the holding tool. Using the correct wrench, turn the fan clutch nut CLOCKWISE to tighten. Tighten firmly to manufacturer specification (verify exact torque in the service manual). The connection should be very snug to prevent loosening during operation.
9. 9

   Reinstall upper fan shroud
   Position the upper fan shroud back around the fan assembly, ensuring the fan blades are centered in the shroud opening with adequate clearance on all sides. Snap the lower shroud clips into the lower shroud receptacles. Install and tighten the two 10mm bolts at the top of the shroud to the radiator support.

Reassembly

1. Reconnect the negative battery cable
2. Reinstall the engine cover if previously removed
3. Verify all tools and parts have been removed from the engine bay

Verification

• Start the engine and verify the fan spins freely without wobble or unusual noise
• Allow engine to reach operating temperature and confirm the fan clutch engages (fan speed increases noticeably and pulls more air)
• Check for proper fan-to-shroud clearance with engine running
• Listen for any rubbing, grinding, or bearing noise from the fan clutch
• Verify cooling system operates normally and engine temperature remains in normal range

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