Peterbilt 579 - Engine Fan

ENGINE
Engine Fan
WARNING!
Do not work on the fan with the engine
running. The engine fan can engage
at any time without warning. Before
turning on the ignition, be sure that no
one is near the fan. Failure to comply
may result in death or personal injury.
Your
truck may be equipped with an
On/Off or Viscous Fan Drive. Follow
these guidelines to check your engine
fan:
• Check the fan bearings for fan
hub bearing looseness, loss
of lubricant and any abnormal
conditions. (For example, fan
belt misaligned or excessive
wear/damage.) Before starting the
engine and with the engine off,
look and feel for looseness in the
fan hub.
• With the engine idling and the
hood open, stand at the front of
the vehicle. Listen for any noises
coming from the fan hub. Bearings
that have lost lubricant, and are
dry, will typically emit a squeal
or a growl when the engine is at
operating temperature and the
fan clutch is engaged. If noise is
detected, have the fan bearings
inspected by an authorized
dealership.
Fan Drive
and Blade
WARNING!
Do not work on the fan with the engine
running. The engine fan can engage
at any time without warning. Before
turning on the ignition be sure that no
one is near the fan. Failure to comply
may result in death or personal injury.
Fan Blade
Clearance: Around the fan
shroud, the recommended distance
is 1 in. (25 mm) from front edge of
any fan blade-to-radiator side member.
Minimum clearance is 3/4 in. (19 mm).
• Rear edge of any blade must be
no closer than 3/8 in. (9 mm) to
the nearest engine component. If
this cannot be obtained, the fan
spacer or fan is not correct.
• The leading edge of any fan blade
must be 1 in. (25 mm) from the
inside edge of the shroud.
(04/13) Y53-6047–2C 5-97
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