Detroit Diesel 4000 Series, Service Manual, Page: 2688 / 2706

SERIES 4000 12/16V SERVICE MANUAL
Electrical
All electrical connections should be checked for tightness after each 5,000 hours. All electrical
lines should be checked for breaks and frays. Check to ensure all grounding points are intact.
Thermostat
The engine thermostat operation should be checked according to engine manufacturer’s
specifications and recommendations.
Fan Clutch
After each 1,000 hours, the fan clutch should be checked for signs of internal wear as follows:
1. Bearing wear: With the engine off and no oil supplied to the fan clutch, push the fan
forward, then rearward. No end play should be found.
NOTE:
For the next tests, it is necessary to provide an external supply of oil pressure at 40 psi
minimum, 100 psi maximum. The oil supply should be compatible with the oil being
used in the engine.
2. Clutch Plate Drive Slot Wear: With the engine off and the clutch locked by means of
the external oil supply, rotate the fan with a light force clockwise/counterclockwise.
Movement at a point 30 in. from the center of the fan blade should not exceed 1.00 in.
Excess movement indicates excessive wear at the drive tangs.
3. Clutch Plate Wear: With the engine off, apply 40 psi oil pressure to lock up the clutch.
Using the pull-type scale connected to the fan blade 30 in. from the center of the fan, a
pull of no less than 230-250 lbs should be required to rotate the blade independently
of the pulley.
All information subject to change without notice.
F-8
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