Water Pump Cleaning and Inspection (G/C3500HD/Medium Duty)

Tools Required 

J 41240  Fan Clutch Wrench

1. Remove the water pump pulley bolts using the J 41240  in order to prevent water pump pulley rotation.
2. Remove the water pump pulley.
3. Inspect the water pump pulley for damage at the belt contact area and the pulley-to-water pump mounting surface.
   Fig 1: Removing Water Pump Pulley Bolts Using J 41240

   Courtesy of GENERAL MOTORS CORP.

   Important:  Do not immerse the water pump in solvent. The solvent may enter the water pump's permanently lubricated bearings and cause premature bearing failure.

4. Clean all excess dirt and debris from the water pump housing.
5. Inspect the water pump for the following:
   • Leakage at the hose fitting (1)
   • Leakage at the water pump weep hole (3)

     A stain around the weep hole is acceptable. If leakage occurs (dripping) with the engine running and the cooling system pressurized, replace the water pump.

   • Gasket sealing surfaces (2) for excessive scratches or gouging
   • Restrictions within the internal coolant passages (4)
   • Excessive side-to-side play in the pulley shaft (5)

     If the shaft end play exceeds 0.381 mm (0.015 in), replace the water pump.

   • Rotate the pump shaft by hand and inspect for roughness of operation
     • If the hub wobbles, is noisy, or feels rough when rotated, replace the water pump.
     • The shaft and fan hub must turn straight and smoothly.
   • Damage to threaded bolt holes (6)
   • Damage to the fan clutch mounting threads (5)
   Fig 2: Water Pump Pulley Inspection Areas

   Courtesy of GENERAL MOTORS CORP.
6. Install the water pump pulley.
   NOTE: Refer to FASTENER NOTICE in Cautions and Notices.
7. Install the water pump pulley bolts using theJ 41240  in order to prevent water pump pulley rotation.

   Tighten 

   Tighten the water pump pulley bolts to 25 N.m (19 lb ft).

   Fig 3: Installing Water Pump Pulley Bolts Using J 41240

   Courtesy of GENERAL MOTORS CORP.