ENGINE WARM–UP AND IDLING STARTING AND OPERATING THE VEHICLE
– 92 – Y53-6033
Regional Haul (R05/10)
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 warm-
up with the engine at 900 to 1000 rpm for 3 to 5 min-
utes.
• 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 pres-
sure to stabilize. In extremely cold temperatures,
you may have to increase idle speed.
NOTE: In colder climates where the tempera-
tures are often below freezing, sufficient warm-
up for turbocharged engines is especially impor-
tant. Chilled external oil lines leading to the tur-
bocharger will slow the oil flow until the oil
warms, reducing oil available for the bearings.
Watch the engine oil pressure gauge for a
warming trend before increasing engine idle
speed (rpm).
3. Continue the engine warm-up until the coolant tem-
perature reaches at least 130°F (54°C). At this tem-
perature, you can use partial throttle. Wait until the
coolant temperature is at least 160°F (71°C) before
operating at full throttle. See “Operating Manual
Transmissions” on page 96.
