WARNING
Make sure the batteries are disconnected before
checking the fan clutch. If the engine starts during
this procedure, the fan could engage, which could
result in serious personal injury.
2.
Inspect the electrical connections and wires to
the fan clutch solenoid. Secure the connection if
loose; replace wires and connectors if damaged.
3.
Clean the fan clutch air solenoid valve filter, if
equipped.
3.1
Unscrew the fan clutch solenoid valve air
filter assembly, and remove the filter ele-
ment.
3.2
Clean the filter element with cleaning sol-
vent.
3.3
Using a clean, lint-free cloth, wipe off any
excess solvent.
3.4
Reassemble the clutch valve solenoid air
filter assembly, and install it on the ve-
hicle.
4.
Visually check the fan for bent, cracked, or dam-
aged blades. Replace if damaged. Check for ad-
equate clearance between the fan and other
components.
5.
Check the fan belt for wear, tension, and align-
ment. Correct, if necessary.
6.
Check for wear on the friction facing. Replace
the friction facing if it is worn to a 3/16-inch (4.8-
mm) thickness or less. Also check the facing for
signs of oil contamination or burn marks. If evi-
dence of oil or burn marks are found, replace the
friction facing.
7.
Connect the battery cables. Start the engine, and
charge the air system to 120 psi (827 kPa).
Manually engage and disengage the fan clutch.
Check the fan and the fan clutch from a dis-
tance. Look for vibration, fan blade contact, fan
clutch slippage, and overall fan clutch operation.
If the fan clutch does not operate correctly, see
Group 20
of the
Business Class® M2 Workshop
Manual
for troubleshooting and repair proce-
dures.
8.
With the air system charged to 120 psi (827
kPa), check the fan clutch for audible air leaks,
using a suitable listening device.
Check at the solenoid valve, the air filter assem-
bly, and the air hoses and fittings. See
Using a wet finger or a soapy water solution,
check for a leak in the same areas.
9.
If a leak is detected, remove the fan blade. In-
stall a new seal kit. See
Group 20
of the
Business Class® M2 Workshop Manual
for repair
procedures.
10. Check the fan drive for discoloration or any other
signs of slipping or overheating.
NOTE: The fan clutch may slip if the air supply
pressure is below 70 psi (483 kPa) or if there is
a leak inside the fan clutch. Any leak must be
remedied.
11. Check the fan clutch bearings.
11.1
Turn the fan in both directions and feel
for worn hub bearings.
11.2
If possible, remove the drive belt and
check for worn sheave bearings by turn-
ing the sheave in both directions.
11.3
If either the hub or sheave bearings are
worn, replace them, using a Horton Drive-
Master Super Kit.
For instructions and kit part number, see
Group 20
of the
Business Class® M2
Workshop Manual
.
f200581
10/05/2016
Fig. 1, Checking for Air Leaks (Horton DriveMaster)
Engine Cooling/Radiator
20
Business Class M2 Maintenance Manual, August 2015
20/3
Property of American Airlines
