Dodge 2008 Ram Pickup 3500 - Manual (Page 266)

If temperatures are below 32°F (0°C), operate the engine
at moderate speeds for 5 minutes before full loads are
applied.
Engine Idling — In Cold Weather
Avoid prolonged idling in ambient temperatures below
0°F. Long periods of idling may be harmful to your
engine because combustion chamber temperatures can
drop so low that the fuel may not burn completely.
Incomplete combustion allows carbon and varnish to
form on piston rings and injector nozzles. Also, the
unburned fuel can enter the crankcase, diluting the oil
and causing rapid wear to the engine. Excessive idle time
can also cause damage to the engine exhaust aftertreat-
ment system.
NOTE: An optional driver-controlled high idle speed is
available on automatic transmission equipped vehicles
with speed control. This feature allows the driver to
select an elevated idle speed between 1100 and 1500
rpms. Your dealer can enable this feature.
NOTE:
• If ambient temperatures are low and the coolant
temperature is below 200°F (93°C), the engine idle
speed will slowly increase to 1000 RPM after 2 minutes
of idle, if the following conditions are met:
• foot is off brake pedal and throttle pedal
• automatic transmission is in Park (P)
• vehicle speed is zero
• Applying the throttle will cancel fast idle
• If the engine is equipped with an exhaust brake,
operating the exhaust brake at idle will greatly im-
prove warm up rate and will help keep the engine
close to operating temperature during extended idle.
266 STARTING AND OPERATING