Leave the negative wire on the battery connected for now. First, pull out the air cleaner plastic intake tube, then unfasten the shroud from the bottom half and the top half. Enable the water pump hub to rotate by turning the mounting nut counterclockwise while using the Snap-On 36 MM Fan Wrench, number SP346 from Snap-On Cummins Diesel Tool Set 2017DSP and Special Tool 6958 Spanner Wrench and Adapter Pins 8346; the thermal viscous fan drive/fan blade assembly is also threaded onto the water pump hub shaft. Make sure at this point not to remove the fan blade assembly from the viscous fan drive. When the thermal viscous fan drive is removed, place it in a position so silicone fluid does not reach the bearing assembly. After that, remove the four bolts holding the fan blade assembly to the viscous fan drive. Clean the fan blades using a mix of mild soap and water; don't use any harsh scrubbing brushes. Check the assembly carefully for damaged rivets, any misshapes, bends, cracking or cracks that might be caused by broken welds and change the fan if damage is found. If you exchange the fan blade assembly because it is damaged, be sure to inspect the water pump and viscous fan drive for possible harm from too much vibration. Bolts should be tightened on the fan blade to 23 Nm torque (17 ft. lbs.) while it is connected to the viscous fan drive, followed by placing the fan blade/viscous fan drive assembly over the water pump shaft and sliding on the fan shroud and intake tube. Reconnect the negative battery cable to complete installation.