Locking Radiator Fan Clutch For Emergency Operation; Electrical Locking; Mechanical Locking In Case Of Power Failure; Maintenance - PREVOST H3-41 Maintenance Manual

SECTION 05A: H3 SERIES COOLING SYSTEM
14.1 LOCKING RADIATOR FAN CLUTCH
FOR EMERGENCY OPERATION

14.1.1 Electrical Locking

If the radiator fan clutch does not function due to
an electrical control system malfunction and the
engine is overheating, you can activate the fan
clutch through one of the Driver Information
Display menus. For more detail, refer to "Forced
Activation of the Radiator Fan Clutch" paragraph
in Section 06: ELECTRICAL.
NOTE
If the fan clutch does not engage using this
procedure then the clutch is faulty or the
wiring between the multiplex module and the
clutch is faulty. Mechanically lock the fan as
described in paragraph 14.1.2.
14.1.2 Mechanical Locking In Case Of Power
Failure
Once mechanically locked, the fan clutch is
rigidly connected to the drive mechanism and
will rotate continuously, with no considerations
for the cooling needs. This is an emergency
situation and the vehicle shall not be operated in
that situation for an extended period.
In case of a magnetic clutch malfunction:
1. Set the ignition to the OFF position and
remove the key from the contact switch to
prevent accidental starting of the engine.
2. Disconnect the
connector.
3. Unscrew and remove the 4 spare M6x12 hex
bolts screwed to the angle on the fan
gearbox mounting support (FIGURE 40).
4. Screw in 4 hex bolts through the clutch
anchor plate into the rotor. Using the
automatic belt tensioner, release tension on
the drive belt in order to be able to rotate the
fan clutch drive mechanism by hand.
TORQUE: 7.5 lb-ft (10 Nm)
26 PA1621 Maintenance Manual All Series | January 2017
fan clutch electrical
FIGURE 40: MECHANICAL LOCKING
14.2

MAINTENANCE

1. Clean the fan and related parts with clean
fuel oil and dry them with compressed air.
Do not clean with steam or high-pressure jet.
2. Check the fan blades for cracks or other
damage. Replace the fan if the blades are
cracked or deformed.
3. Remove any rust or rough spots in the
grooves of the fan drive mechanism pulley. If
the grooves are damaged or severely worn,
replace the pulley.
4. Do not restrict fan rotation during engine
operation for any reason.
5. Do not operate fan driving mechanism with a
damaged fan assembly. Replace a damaged
fan as soon as the fault is noted.
6. Immediately investigate and correct any
operator complaint
mechanism or cooling system performance.
7. When questions arise, obtain answers before
proceeding. Assistance is available through
the Prevost After-Sales Service support
serving your area.
14.3

INSPECTION

WARNING
Set the starter selector switch in engine
compartment to the "OFF" position to prevent
accidental starting of the engine.
 Check security of fasteners securing fan
blade assembly to right angle gearbox.
 Visually inspect fan driving mechanism, fan
blade assembly,
surrounding area for evidence of contact
between rotating and non-rotating parts.
involving driving
shroud, radiator, and