GMC 2003 C4C042 Owner's Manual page 103

D
The voltmeter charge indicator gage tells you the
condition of your battery's charge. The gage should
be in the center area during engine operation. The
red area on the left indicates an undercharge
condition; the red area on the right indicates an
overcharge. If the gage is in either red area, have the
battery and charging system checked right away.
NOTICE:
For diesel engines, don't allow the engine to
operate at low idle for more than five minutes.
This can cause low engine operating
temperatures which can affect engine operation
and reduce engine life. Engine idle speed should
be increased to 1200 rpm whenever extended idle
is required. Once started, the engine should be
placed under load to allow the engine coolant
temperature to reach 150
shutting off the engine.
2-28
_ _
F (66 C) before
Engine Coolant Heater (If Equipped)
_
In very cold weather, 0 F (
coolant heater can help. You'll get easier starting and
better fuel economy during engine warm
the coolant heater should be plugged in a minimum of
four hours prior to starting your vehicle.
If your vehicle is equipped
with this feature, the plug
receptacle is located under
the driver's door.
_
-
18 C) or colder, the engine
-
up. Usually,
-
in