Mack CHM 2010, Operator'S Handbook Manual

Page: 138 / 232

130 OPERATION
Engine Idling
Idling the engine unnecessarily for long periods of time wastes fuel, fouls injector nozzles
and can lead to valve carbon and varnish deposits. Unburned fuel causes carbon formation
and oil dilution. Shut the engine down when prolonged loading or unloading of cargo is
required.
When starting a cold engine, or if the vehicle has been parked and the engine coolant has
fallen well below normal operating temperature, a fast idle speed of approximately 1200
rpm should be maintained to help the engine warm up more quickly.
Shutting Down the Engine
Standard Shutdown
After a hard run, allow the engine to idle three minutes before shutdown in order to stabilize
the temperature of all engine parts. Quick shutdowns can cause engine damage and prevent
the turbocharger from being properly lubricated.
CAUTION
Operating the engine below normal
operating temperature for extended periods
of time will allow varnish/carbon deposits
to build up on the valve stems and guides.
This will cause the valves to stick in the
guides after the engine has been shut down
and could result in push rod damage when
the engine is restarted. If the engine has
been operated below normal operating
temperature for an extended period of time
(and the odor of raw diesel fuel is detected
or unburned fuel can be seen at the exhaust
stack), the engine should be operated under
"load" until normal operating temperature
is achieved BEFORE shutting down the
engine.