Navistar WorkStar Series, Operator'S Manual

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Operation
• Maintain a minimum of 1250 RPM idle by use of the hand
throttle. Always make sure that parking brake is applied and
transmission is in (N) Neutral before applying hand throttle.
• Maintain engine cooling system.
• Do not shut engine down after extended idling period. Drive
the vehicle under load for several miles at normal operating
temperatures to burn off any accumulated carbon in the
exhaust DPF.
• Consider use of engine block heaters, approved
winter-fronts, and/or radiator shutters where conditions
warrant.
Winter Front Usage
Unless extremely cold conditions exist, the use of winter fronts
or other air restrictive devices mounted in front of the radiator
is not recommended on vehicles which are equipped with
engine charge air coolers. Cooling air flow restriction affects
emissions and can cause high exhaust temperatures, power
loss, excessive fan usage, and a reduction in fuel economy.
If you insist on using a winter front, the device should have a
permanent opening above or directly in line with the fan hub.
The opening’s minimum dimension must be at least 120 in.
(774 cm).
Hot Weather Operation
1. Keep cooling system filled with clean permanent
anti-freeze solution to protect against damage by
overheating.
2. Fill fuel tank at end of daily operation to prevent
condensation in tank.
3. Keep external surface of engine, radiator, charge air
cooler, AC condenser, and accessories clean to avoid
dirt build-up.
Excessive coolant temperature could be experienced while
driving in a transmission gear ratio, which would lug the engine.
To correct the problem, engine speed should be increased
by down shifting into the next lower gear to increase engine
RPM’s which will increase coolant flow through the radiator and
increase fan speed.
Starting A Turbocharged Vehicle On A Grade
Once the clutch is engaged on a turbocharged diesel engine,
the RPM falls off significantly. This is due to the emission control
device that controls the fuel input during first gear acceleration.
When engine RPM first falls off, do not disengage the clutch and
try to increase engine RPM. Doing so may damage driveline
components.
After the initial drop in speed, the engine will
recover and accelerate in a normal manner.
Proper Starting Procedure
Set the spring brakes or hand brake, if equipped, bring the RPM
up slightly and begin to engage the clutch while, at the same
time, releasing the spring brakes.
As the RPM begins to fall off, DO NOT disengage the clutch. The
RPM will quickly come back and the vehicle will move steadily
up the grade.
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