The fan shroud must be installed correctly, be in good condition, and the shroud-to-fan clearance must be within the manufacturer’s specifications to make sure proper air flow through the radiator exists to provide adequate engine cooling.
Inspect the fan shroud for proper fan clearance, cracks, air leaks, or damage. Replace if necessary. Refer to the OEM service manual.
Cummins Inc. recommends fan clearance be 5.08 to 10.16 cm [2 to 4 in] from the radiator core. Refer to the OEM service manual for alternative positions.