Medium Duty Operator's Manual - Peterbilt Motors Company

STARTING AND OPERATING THE VEHICLE
With each engine make, the air intake heating system
works differently. To understand fully how your engine's
heating system operates, see the engine Operation and
Maintenance Manual for details.
On most systems the engine block temperature is monitored
at startup; other systems monitor the engine oil
pressure, coolant temperature, and time, as well. When
the pre-set conditions are met, the heater automatically
engages.
Air Intake Heater
The air intake heater system will alert you when the
engine requires preheat. On the dash is a “WAIT TO
START” warning light (See page 26). This light alerts you
to wait before starting the engine.
Turn the key to IGN & ACC: the WAIT TO START light will
light up for bulb check.
Wait until the WAIT TO START light goes off before you
start the engine.
When the WAIT TO START light goes off, the preheat
cycle is complete and you can start the engine normally.
After the engine starts and until operating conditions
reach a certain point, the system will continue to operate
to eliminate white-smoke exhaust.
Engine Warm–Up and Idling
The purpose of engine warm-up is to allow an oil film to be
established between pistons, shafts, and bearings while
your engine gradually reaches operating temperature.
Warm–Up Procedure
1. After you have started the engine, idle the engine at
approximately 600 rpm while you check vital engine
systems:
– oil pressure
– air pressure
– alternator output (with the optional voltmeter)
2. Before placing engine under a load, continue warmup
with the engine at 900 to 1000 rpm for 3 to 5 minutes.
• When a cold engine is started, increase the engine
speed (rpm) slowly to be sure adequate lubrication
is available to the bearings and to allow the oil pressure
to stabilize. In extremely cold temperatures,
you may have to increase idle speed.
– 92 – Y53-6008A Medium Duty (R05/09)