freightliner COLUMBIA CL112 Maintenance Manual page 46

Engine Cooling/Radiator
20–03 Fan Clutch Check (Noise
Emission Control)
Horton Advantage
NOTE: If any part of the fan clutch needs to be
repaired or replaced, after performing the
checks below, see Group 20 of the Columbia
Workshop Manual .
1. Disconnect the batteries at the negative termi-
nals. Drain all air from the air system. If
equipped with an air starter, drain the air starter
reservoir.
WARNING
If the engine starts during this procedure, the fan
could cause personal injury. If the vehicle is
equipped with an air starter, be sure that the air
starter reservoir is drained.
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 and remove its element.
3.2 Clean the filter element with cleaning sol-
vent.
3.3 Reassemble the clutch valve solenoid air
filter, then install it.
4. Check the fan for bent, cracked, or damaged
blades. Replace if damaged. Check for adequate
clearance between the fan and other compo-
nents.
5. Check the fan belt for wear, tension, and align-
ment. Correct as needed.
6. Check for wear on the friction facing. See
Replace the friction facing if it is worn to a 1/16-
inch (1.6-mm) thickness or less. Also check the
facing for signs of oil contamination or burn
marks. If evidence 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). Shut
Columbia Maintenance Manual, January 2007
®
Fan Clutch
®
Fig. 5.
08/08/94
1. System Sentry ® Fuse
2. Safeguard Hole
3. Friction Facing
Fig. 5, Horton Advantage Fan Clutch
down the engine. Separate the halves of the fan
solenoid connector. The fan clutch should en-
gage.
If the fan does not operate correctly, see Group
®
20 of the Columbia
troubleshooting and repair procedures.
8. With the air system charged to 120 psi (827
kPa), and with the fan solenoid connector halves
separated, check the fan clutch for audible air
leaks, using a suitable listening device.
9. If a leak is detected, remove the fan blade. Using
a soapy water solution, check the fan clutch at
the following locations to find the source of the
leak. Install a new seal kit. See Group 20 of the
Columbia ® Workshop Manual for repair proce-
dures.
9.1 Check for a leak at the bleed hole on the
fan pilot. Air leakage means the cartridge
assembly (Fig.
(Ref. 17) is damaged.
9.2 Check for air leaks between the air cham-
ber and the piston friction disc. Air leak-
age means the large O-ring (Ref. 14) is
damaged.
9.3 Check for air leaks around the safeguard
hole on the piston friction disc. Air leak-
age means the small O-ring (Ref. 18) is
damaged.
9.4 Check for air leaking from the System
®
Sentry fuse. Leaking air means the
clutch has gotten so hot the lead alloy in
20
3
4
5
2
1
f200290
4. Piston Friction Disc
5. Air Chamber
Workshop Manual for
6, Ref. 16) or face seal
20/5