freightliner 122SD - Cold-Weather Operation

The operating range extends from maximum torque
rpm at the low end to engine rated speed at the high
end. Most engines deliver best fuel economy when
operated in the low- and mid-speed segments of the
efficiency range and produce maximum horsepower
at rated speed, which is also the recommended
maximum speed of the engine. For specifics for any
engine refer to the engine manufacturer’s operation
manual.
Prolonged idling of engines is not recommended, and
is illegal in some states. The belief that idling a die-
sel engine causes no engine damage is wrong. Idling
produces sulfuric acid, that is absorbed by the lubri-
cating oil, and eats into bearings, rings, valve stems,
and engine surfaces. If you must idle the engine for
cab heat or cooling, the high idle function of the
cruise control switches should be used. An idle
speed of 900 rpm should be enough to provide cab
heat in above freezing ambient temperatures.
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
(CHECK ENGINE lamp flashing) 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 so equipped, turn off the load disconnect
switch after the engine is shut down, to prevent
battery 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;
Engine Starting, Operation, and Shutdown
9.3