Ram Trucks 2015 Chassis Cab Commercial - Diesel Supplement - Manual (Page 225)

If temperatures are below 32°F (0°C), operate the engine
at moderate speeds for five minutes before full loads are
applied.
NOTE:
If ambient temperatures are low and the coolant
temperature is below 180°F (82°C), the engine idle speed
will slowly increase to 1,000 RPM after two minutes of
idle, if the following conditions are met:
• Foot is off brake pedal and throttle pedal.
• Automatic transmission is in PARK.
• Vehicle speed is 0 mph (0 km/h).
• Applying the throttle will cancel fast idle.
• 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.
Engine Idling
Avoid prolonged idling, 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, engine valves, and
injector nozzles. Also, the unburned fuel can enter the
crankcase, diluting the oil and causing rapid wear to the
engine.
If the engine is allowed to idle, under some conditions
the idle speed may increase to 900 RPM then return to
normal idle speed. This is normal operation.
NOTE:
For EVIC/DID messages related to the vehicle’s
exhaust system, refer to “Electronic Vehicle Information
Center (EVIC)” or “Driver Information Display (DID)”
for further information.
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