OPERATOR'S MANUAL

Engine Cooling System Preventive Maintenance
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Medium Duty (R05/09)
To Check the Fan:
• Check the fan assembly mounting bolts for tightness.
Inspect the blades for damage.
• Check the clutch operation by starting the engine when it
is cold. Then idle it at about 800 RPM. Listen for air
leaks.
• Check that the fan is not working while the engine is
warming. When the clutch engages, note the reading on
the vehicle's panel—mounted coolant temperature
gauge. If the fan clutch engages at low engine tempera-
ture or cycles on and off more frequently than it should
(receives “false signals”), have the problem corrected at
an Authorized Service Center.
Fan Drive and Blade
Fan Blade Clearance: Around the fan shroud, the recom-
mended 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.
Exhaust System
The exhaust system is part of the noise control system. Peri-
odically check the exhaust for wear and loose or missing
parts. For details, see
“Noise and Emission Control” on
page 257
.
WARNING! The exhaust piping, muffler, con-
verter muffler or independent converter become
extremely hot during engine operation and can
cause death or personal injury including serious
burns to the skin. Allow adequate cooling time
before working on or near any part of the
exhaust system.
Engine Cooling System
Your engine’s cooling system is standard with Extended
Life Coolant (ELC). ELC consists of a mixture of ethylene
glycol, water, and organic acid technology chemical inhib-