Peterbilt Medium Duty Trucks Operator's Manual after 1-07

Preventive Maintenance
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 temperature
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 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.
Engine Cooling System
• 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. Periodically
check the exhaust for wear and loose or missing
parts. For details, see “Noise and Emission Control” on
page 220.
WARNING! The exhaust piping, muffler, converter
muffler or independent converter become
extremely hot during engine operation and can
cause 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 inhibitors.
ELC prevents corrosion and scale formation as well
as provides freezing and boiling point protection.
Medium Duty (R10/06) Y53-6008 – 143 –