also the recommended maximum speed of the en-
gine. For further engine-specific information, refer to
the engine manufacturer’s operation manual.
Prolonged idling of engines is not recommended, and
is illegal in some states. Idling produces sulfuric acid,
that is absorbed by the lubricating oil, and eats into
bearings, rings, valve stems, and engine surfaces. If
you must idle the engine for cab heat or cooling, use
the high idle function of the cruise control switches.
An idle speed of 900 rpm should be enough to pro-
vide cab heat in above freezing ambient tempera-
tures.
If the engine is programmed with the idle shutdown
timer, ninety seconds before the preset shutdown
time, the CHECK ENGINE light will begin to flash at
a rapid rate. If the position of the clutch pedal or ser-
vice brake changes during this final ninety seconds
the idle shutdown timer will be disabled until reset.
Cold-Weather Operation
Satisfactory performance of a diesel engine operating
in low ambient temperatures requires modification of
the engine, surrounding equipment, operating prac-
tices, and maintenance procedures. The lower the
temperature, the greater the amount of modification
required. For service products approved for use in
cold weather for your engine, see the engine manu-
facturer’s engine operation manual, supplied in the
vehicle documentation package.
If satisfactory engine temperature is not maintained,
maintenance costs will increase due to greater en-
gine wear. If the engine coolant temperature be-
comes too low, raw fuel will wash the lubricating oil
off the cylinder walls and dilute the crankcase oil,
causing all moving parts of the engine to suffer from
poor lubrication.
If the engine is in good mechanical condition and the
precautions necessary for cold-weather operation are
taken, ordinary cold weather will not cause difficulty
in starting or loss of efficiency.
The following points are important to observe when
operating in cold weather:
•
Check for cracks in the batteries, for corrosion
of the terminals, and for tightness of the cable
clamps at the terminals.
•
Charge the batteries to full capacity. Replace
any battery that is damaged.
•
If equipped, turn off the load disconnect switch
after the engine is shut down, to prevent bat-
tery discharge.
•
Have the alternator output checked at an au-
thorized service provider.
•
Check the condition and tension of the drive
belts.
•
Refer to the engine manufacturer’s engine op-
eration manual for recommended heaters, low-
viscosity lubricating oils, wintergrade fuels, and
approved coolants.
NOTICE
For Detroit engines (EPA07 and newer), use of a
winterfront is not recommended, as it can cause
false fault codes with the engine and aftertreat-
ment system, and possible emission component
failures.
If using a winterfront, leave at least 25% of the grille
opening exposed in sectioned stripes that run per-
pendicular to the charge-air-cooler tube-flow direc-
tion. This assures even cooling across each tube,
and reduces header-to-tube stress, and possible
chance of component failure. For engine-specific
guidelines, see below:
Cummins and Mercedes-Benz engines:
A winterfront
may be used to improve cab heating while idling, and
only when the ambient temperature remains below
10°F (-12°C).
Detroit engines (EPA07 and newer):
Use of a winter-
front is not recommended. Using a winterfront can
cause excessive fan run time, increased fuel con-
sumption, and failure of the DEF system heaters to
operate correctly, resulting in fault codes, poor per-
formance, and power reduction. A winterfront should
only be used temporarily in the following situations:
•
to improve cab heating while idling in an ex-
tremely cold ambient temperature;
•
when the ambient temperature remains below
-22°F (-30°C) and the engine is unable to
maintain a running coolant temperature of
175°F (80°C) during normal over-the-road op-
eration.
High-Altitude Operation
Engines lose horsepower when operated at high alti-
tude because the air is too thin to burn as much fuel
as at sea level. This loss is about three percent for
Engines
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