Engine Checks Before Operating - GMC 2005 T-Series Owner's Manual

Engine Checks Before Operating

When you have started your engine, let it run for
20 to 30 seconds before you put a load on the engine.
But do not leave the vehicle while the engine is running.
Avoid unnecessary idling of diesel engine equipped
vehicles.
If the engine idles too long, the temperature of the
engine coolant will fall below the normal operating
range. Low engine operating temperature causes
several conditions which affect engine operation and
reduce engine life.
The engine should be permitted to go through a
warm-up period. Operate the vehicle at a minimum of
600 rpm during the warm-up period. During this
period and during operation, the following observations
should be made.
2-12
During this warm-up period, check your warning lights
and gages:
•
If oil pressure does not begin to rise within
15 seconds of starting, stop the engine and find the
cause. See Oil Pressure Gage on page 3-32 for
more information.
•
If the engine coolant temperature gage needle goes
into the hot area on the gage, stop the engine and
find the cause of the overheating. See Engine
Coolant Temperature Gage on page 3-30 for more
information.
•
If you have air brakes, the dual-needle air pressure
gage should read at least 115 psi (790 kPa) for both
service systems before you try to move the vehicle.
When air pressure is below 60 psi (420 kPa), the
LOW AIR light will come on and you will hear a tone
alarm. See Brake System Warning Light on
page 3-27 for more information. If the pressure does
not build up or drops during warm-up, stop the
engine and find the cause before you try to move the
vehicle. Recommended air pressure before driving is
120 psi (830 kPa). See Air Pressure Gage on
page 3-38 for more information.