2003 CHEVROLET C/K engine

2-20 Cold Weather Starting
(Caterpillar

Diesel)
Because the diesel engine uses compression ignition, it
is harder to start in cold weather than a gasoline engine.
The air intake heater and use of the proper engine oil,
optional engine coolant heaters and optional ether
injection systems help cold weather starting. See the
Caterpillar

Diesel Engine Operation & Maintenance
Manual for more information.
NOTICE:
Your diesel engine has an electric air intake
heater system which reduces white smoke and
helps start the engine in cold weather. Do not
spray starting fluid into the air intake where it
can contact the heater elements.
If you don't have the GM Automatic Ether
Injection System, don't use starting fluid or you
could damage your engine. If you have the GM
system, use only GM approved starting fluid that
has been tested to establish compatibility with the
air inlet heater system.
Diesel Engine Warm-Up
Several factors affect how quickly your diesel engine
warms up. These can include outside temperature,
engine load, idle time and your vehicle's option content.
Your vehicle may be equipped with some features that
can help the engine reach operating temperature sooner.
Some of these features are discussed below.
Also, remember that an automatic transmission adds
heat to the cooling system through the heat exchanger in
the radiator. Because of this, vehicles equipped with
automatic transmissions are often able to retain engine
coolant heat better than manual transmission vehicles.
See your Caterpillar

Operation & Maintenance manual
for additional diesel engine warm
-up information.

2-21 Engine Alarm and Automatic Shutdown
(If Equipped)
Your check gages light will come on if the system senses
high engine temperature or low engine oil pressure. If high
engine temperature or low engine oil pressure is detected,
you will also hear a tone alarm at two beats per second.
The alarm and the light will remain on until the condition
is fixed. If the engine temperature or oil pressure condition
worsens, the tone alarm will go to five beats per second.
If the system senses low engine coolant, the five beat
per second alarm and the low coolant warning light will
come on.
The five beats per second tone alarm means that your
engine will shut down in approximately 25
-30 seconds.
There is also an engine shutdown light to indicate that
the engine will shut down. See ªAutomatic Engine
Shutdown Lightº later in this section.
Pull off the road and shut off the engine. Don't start it
until the reason for the problem is known, and the
problem is fixed. If the engine shuts down when you are
still in traffic, you can restart the engine and get another
25
-30 seconds of operation. Do this only if you have to,
since there is a problem that can harm the engine if it
isn't fixed. Engine automatic shutdown, for gasoline
engines, requires activation by your dealer.
High Idle System (Caterpillar
Diesel
and Gasoline Engines)
Your vehicle has both automatic and manual high idle
capabilities.
Automatic High Idle System (Diesel Engines)
(If Equipped)
The automatic high idle feature will engage whenever
you start your vehicle and the engine is below the preset
operating temperature. This will help decrease engine
warm
-up time.
Idle speed will then return to normal under any of the
following conditions:

The engine reaches the preset operating temperature
or has been operating for at least ten minutes.

The brake pedal is pressed.

The manual transmission clutch pedal is pressed or,
the automatic transmission (if equipped) is shifted
from NEUTRAL (N) or PARK (P).

The vehicle speed exceeds approximately
5 mph (8 km/h).

The throttle is pressed.

2-23 Exhaust Restrictor (Diesel Engines)
(If Equipped)
If your vehicle is equipped with this feature, there is an
exhaust restrictor valve located in the exhaust stream.
The valve closes to provide back pressure to the engine
for the purpose of warming the engine quickly.
The exhaust restrictor operates:

while the engine is running.

while the vehicle is not moving.

while the accelerator, brake and clutch pedals are
not pressed.

while idling or driving in cold temperatures.

when the shift lever is in NEUTRAL (N)
or PARK (P).On vehicles equipped with a diesel engine exhaust
brake, the exhaust brake switch must be on. The
indicator in the exhaust brake switch will be lit when the
exhaust restrictor is active. The exhaust brake indicator
light in the center of the instrument panel will also be lit
whenever the exhaust restrictor is active.
When the engine coolant temperature is below 149F
(65C) and the outside temperature is below 50F
(10C), the exhaust restrictor will come on within
45 seconds of starting the engine. After running the
engine for an additional 45 seconds, the engine idle
will increase.
The exhaust restrictor will shut off and engine idle will
return to normal once the engine is warmed up, or the
transmission is shifted into range.

2-24
Starting Your DURAMAX

Diesel Engine
Your diesel engine starts differently than a
gasoline engine.
Automatic Transmission
Move your shift lever to PARK (P) or NEUTRAL (N).
Your engine won't start in any other position
-- that's
a safety feature. To restart when you're already moving,
use NEUTRAL (N) only.
NOTICE:
Don't try to shift to PARK (P) if your vehicle is
moving. If you do, you could damage the
transmission. Shift to PARK (P) only when your
vehicle is stopped.
Manual Transmission
Move your shift lever to neutral and hold the clutch
pedal to the floor while starting the engine. Your vehicle
won't start if the clutch pedal is not all the way
down
-- that's a safety feature.
Starting Your Engine
1. Turn your ignition key to RUN.
Observe the wait to start light. See ªWait To Start
Lightº in the Index. (This light may not come on
if the engine is hot.)
2. As soon as the wait to start light goes off,
IMMEDIATELY turn the ignition key to START.
When the engine starts, let go of the key.
NOTICE:
Holding your key in START for longer than
15 seconds at a time will cause your battery to be
drained much sooner. And the excessive heat can
damage your starter motor.

2-25
NOTICE:
If the wait to start light stays on, it means that
your vehicle could have one of several problems,
so you should have it serviced right away.
3. If the engine does not start after 15 seconds of
cranking, turn the ignition key to OFF. Wait
one minute for the starter to cool, then try the
same steps again.
If you're trying to start your engine after you've run
out of fuel, follow the steps in ªRunning Out of Fuel.º
See ªDiesel Fuel Requirements and Fuel Systemº in
the Index.
When your engine is cold, let it run for a few minutes
before you move your vehicle. This lets oil pressure
build up. Your engine will sound louder when it's cold.
NOTICE:
If you're not in an idling vehicle and the engine
overheats, you wouldn't be there to see the
overheated engine condition. This could damage
your vehicle. Don't let your engine run when
you're not in your vehicle.
Cold Weather Starting (Diesel Engine)
The following tips will help you get good starting in
cold weather.
Use the recommended engine oil when the outside
temperature drops below freezing. See ªEngine Oilº in
the Index. When the outside temperature drops below
0
F (
-18
C), use of the engine coolant heater is
recommended.
If you experience longer cranking times, notice an
unusual amount of exhaust smoke or are at higher
altitudes (over 7,000 ft. or 2 135 m), you may use your
engine coolant heater. See ªEngine Coolant Heaterº in
the Index.
See ªDiesel Fuel Requirements and Fuel Systemº in the
Index for information on what fuel to use in cold weather.

2-26 If Your Diesel Engine Won't Start
If you've run out of fuel, look at ªRunning Out of Fuel.º
See ªDiesel Fuel Requirements and Fuel Systemº in
the Index.
If you're not out of fuel, and your engine won't start,
do this:
Turn your ignition key to RUN. IMMEDIATELY
after the wait to start light goes off, turn the ignition
key to START.
If the light doesn't go off, wait a few seconds, then try
starting your engine again. And, see your dealer as soon
as you can for a starting system check.
If the light comes on and then goes off and you know
your batteries are charged, but your engine still won't
start, your vehicle needs service.
If the light does not come on when the engine is cold,
your vehicle needs service.If your batteries don't have enough charge to start your
engine, see ªBatteryº in the owner's manual.
Be sure you have the right oil for your engine, and that
you've changed the oil at the proper times. If you use
the wrong oil, your engine may be harder to start.
Be sure you are using the proper fuel for existing
weather conditions. See ªDiesel Fuel Requirements and
Fuel Systemº in the Index.
If the engine starts, runs a short time, then stops, your
vehicle needs service.
CAUTION:
Do not use gasoline or starting ªaids,º such as
ether, in the air intake. They could damage your
engine. There could also be a fire, which could
cause serious personal injury.

2-27
Engine Checks Before Operating
When you've started your engine, let it run for 20 to
30 seconds before you put a load on the engine. But
don't 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.
During this warm
-up period, check your warning lights
and gages:

If oil pressure doesn't begin to rise within
15 seconds of starting, stop the engine and
find the cause.
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.

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. If the pressure doesn't 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 actually driving
away is 120 psi (830 kPa).

The charging system light should come on when
the ignition key is turned to RUN or START and
should go out when the engine is running above idle.
If the light doesn't go out or comes back on during
normal engine operation, have the charging system
checked right away. (This light tells you if the
generator is not charging; it doesn't reflect the
condition of the battery.)

2-28

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 150F (66C) before
shutting off the engine.
Engine Coolant Heater (If Equipped)
If your vehicle is equipped
with this feature, the plug
-in
receptacle is located under
the driver's door.
In very cold weather, 0F (
-18C) or colder, the engine
coolant heater can help. You'll get easier starting and
better fuel economy during engine warm
-up. Usually,
the coolant heater should be plugged in a minimum of
four hours prior to starting your vehicle.