GMC 2003 DURAMAX User manual

Features and Controls ..................................... 2-1
Starting and Operating Your Vehicle ............. 2-2
Instrument Panel ............................................. 3-1
Warning Lights, Gages and Indicators ........... 3-2
Service and Appearance Care .......................... 5-1
Diesel Fuel Requirements and
Fuel System .......................................... 5-2
Checking Things Under the Hood ............... 5-14
Capacities and Specifications ..................... 5-38
Maintenance Schedule ..................................... 6-1
Maintenance Schedule ................................ 6-2
Index ................................................................ 1
2003 DURAMAX™ Diesel Engine M

This manual contains information that pertains to the
operation of your diesel engine. It also contains
your Diesel Maintenance Schedule. The sections in this
manual correspond to the sections in your owner
manual. This manual, along with your owner manual,
will assist you in the proper use and maintenance
of your vehicle.
Keep this manual with the owner manual in your
vehicle, so it will be there if you ever need it while you
are on the road. If you sell your vehicle, leave this
manual and the owner manual with the vehicle.
This manual includes the latest information at the time it
was printed. We reserve the rights to make changes
in the product after that time without notice.
General Motors Corporation. All Rights Reserved.
General Motors, GM, GMC, CHEVROLET, SIERRA and
SILVERADO are registered trademarks of General
Motors Corporation.
Canadian Owners
A French language copy of this manual can be obtained
from your dealer or from:
Helm, Incorporated
P.O. Box 07130
Detroit, MI 48207
Part No. 15063177 First Edition ©Copyright General Motors Corporation 06/24/02
All Rights Reserved
ii

Starting and Operating Your Vehicle .................2-2
Starting Your Diesel Engine .............................2-2 Winter Cover .................................................2-6 Engine Coolant Heater ....................................2-7
Section 2 Features and Controls
2-1

Starting and Operating Your
Vehicle
Starting Your 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: Do not 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 Wait to Start
Light on page 3-6. 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.
If your vehicle is equipped with the RPO LLY
engine, it has a fast warm-up glow plug system.
The wait to start light will illuminate for a much
shorter time than most diesel engines, due to the
rapid heating of the glow plug system.
2-2

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.
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 Running Out of Fuel on
page 5-10. See “Diesel Fuel Requirements and Fuel
System”.
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 are not in an idling vehicle and
the engine overheats, you would not be there to
see the overheated engine indication. This could
damage your vehicle. Do not let your engine
run when you are 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 Engine Oil on
page 5-16. 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 Engine Coolant Heater
on page 2-7.
See “Diesel Fuel Requirements and Fuel System” for
information on what fuel to use in cold weather.
2-3

If Your Diesel Engine Won’t Start
If you’ve run out of fuel, look at Running Out of Fuel
on page 5-10. See “Diesel Fuel Requirements and
Fuel System”.
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 Battery in the owner’s manual index.
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 “Diesel Fuel Requirements and
Fuel System”.
If the engine starts, runs a short time, then stops, your
vehicle needs service.
{CAUTION:
Do not use gasoline or starting “aids” such as
ether, in the air intake. They could damage
your engine. There could also be a fire, which
could cause serious personal injury.
2-4

Elevated Idle/Exhaust Restrictor
If your vehicle is equipped with the RPO LLY engine, it
has a cold temperature high idle and exhaust restrictor
feature which elevates the engines idle speed from
680 to 1200 rpms, and restricts the exhaust gas flow,
when outside temperatures are below 32°F (0°C),
and the engine coolant temperature is below 150°F
(65°C.) This feature enhances heater performance by
raising the engine coolant temperature faster.
This feature can be turned off and on using the DIC
steering wheel control buttons. If your vehicle is
not equipped with the DIC steering wheel control
buttons, doing the following to turn on this feature:
1. Turn the ignition to the run position, with the
vehicle off.
2. Press the accelerator pedal to the floor and hold
while quickly pressing the brake pedal three times
in less than eight seconds.
3. Release the accelerator pedal and start the engine.
When the engine is started, it will slowly ramp up to
the high idle speed after a delay of a few seconds up to
approximately two minutes. For this method to work
properly there must be no throttle or brake pedal faults.
The engine idle speed with return to normal once the
following conditions are met:
•Once engine coolant temperature reaches
150°F (65°C).
•Air intake temperature reaches 32°F (0°C).
The high idle speed will be temporarily interrupted and
the engine speed will return to normal if any of the
following conditions occur:
•The brake pedal is applied.
•The accelerator pedal is pressed.
•The automatic transmission is shifted out of
PARK (P) or NEUTRAL (N).
•The clutch pedal on the manual transmission is
pressed.
•Vehicle speed is detected.
Once these inputs are removed, the engine idle speed
will slowly ramp back up to high idle after the normal
delay, if the conditions for engine coolant temperature
and air intake temperature are still met.
2-5

Winter Cover
If your vehicle includes a winter cover it will enhance
heater performance and will reduce the amount of time
it takes to warm the inside of your vehicle in extremely
cold conditions (below 0°F (-18°C)). The winter
cover installs over the front bumper of your vehicle and
restricts the air flowing to the engine compartment
by covering the radiator grille.
Usage Guidelines
The winter cover should only be used while operating
your vehicle in extremely cold temperatures. In
these temperatures, the vehicle does not need a large
amount of air to properly cool the engine. During periods
of operation when more airflow is required to cool the
vehicle, the winter cover should not be used. The
following usage guidelines will allow adequate airflow for
proper radiator grille and air cooler performance:
•Do not use the winter cover when temperatures are
expected to be above 32°F (0°C). Use of the cover
in these conditions could cause your vehicle to
overheat. If this happens while the cover is being
used, remove the cover.
•Do not use the winter cover if towing a trailer. The
added power needed to tow a trailer requires the
radiator grille to have full airflow under all conditions.
Your vehicle may overheat if the cover is used
while towing a trailer.
•Do not modify the cover. The winter cover does not
cover some sections of the front of the vehicle
because these openings are needed to provide
enough airflow to the radiator grille and air cooler in
extremely cold temperatures.
2-6

Installation Instructions
The following instructions explain how to install and
remove your vehicle’s winter cover. When installing or
removing the cover please refer to the “Usage
Guidelines” mentioned previously. When you first try to
fit the cover it may appear to be undersized. This is
due to the nature of the special vinyl, which will stretch
during installation to insure a tight fit. For this reason,
the initial installation of the cover is best performed when
the winter cover is warm. If you are required to use a
front license plate, simply cut the black stitches on
the back of the patch.
Grille Cover Installation
1. Pre-bend all the small black tabs into the shape
ofaJ.
2. Remove the four push pins and slide them through
each of the pre-punched tabs.
3. Install the four push pins into the grille.
4. Hook all the tabs to the edge of the grille.
5. Fasten the snaps.
Lower Cover Installation
1. Pre-bend all of the small black tabs into the shape
ofaJ. 2. Fasten each tab to
edge of the bumper,
as illustrated.
To remove the winter cover reverse the steps listed
previously.
Engine Coolant Heater
In very cold weather, 0°F (18°C) 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.
2-7

To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord. The
cord is located in the engine compartment, on the
passenger’s side of the vehicle, near the right
side engine mount.
3. Plug it into a normal, grounded 110-volt AC outlet.
{CAUTION:
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the
wrong kind of extension cord could overheat
and cause a fire. You could be seriously
injured. Plug the cord into a properly grounded
three-prong 110-volt AC outlet. If the cord will
not reach, use a heavy-duty three-prong
extension cord rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and
store the cord as it was before to keep it away
from moving engine parts. If you don’t, it could be
damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature.
You may wish to use your coolant heater to improve
ease of starting at temperatures between 0°F (−18°C)
and −20°F (−29°C). Keep the coolant heater plugged in
for a minimum of four hours. However, above −20°F
(−29°C), use of the coolant heater shouldn’t be
necessary. At temperatures below −20°F (−29°C), the
coolant heater should remain plugged in for at least
eight hours. It will not harm either the coolant heater or
the vehicle to leave the coolant heater plugged in
longer than the times stated. Be sure to remove and
store the cord before starting the engine. See “Diesel
Fuel Requirements and Fuel System” for information on
what fuel to use in cold weather.
2-8

Warning Lights, Gages and Indicators ...............3-2
Instrument Panel Cluster .................................3-2
Malfunction Indicator Lamp ..............................3-3
Oil Pressure Gage ..........................................3-5
Wait to Start Light ..........................................3-6
Fuel Gage .....................................................3-6
Driver Information Center (DIC) ........................3-7
Section 3 Instrument Panel
3-1

Warning Lights, Gages and Indicators
Instrument Panel Cluster
United States Version shown, Canada similar.
3-2

Your instrument cluster is designed to let you know at a
glance how your vehicle is running. You’ll know how
fast you’re going, about how much fuel you have
and many other things you’ll need to know to drive safely
and economically.
Malfunction Indicator Lamp
Check Engine Light
Your vehicle is equipped
with a computer which
monitors operation of the
fuel, timing and emission
control systems.
This system is called OBD II (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the
life of the vehicle, helping to produce a cleaner
environment. The Check Engine light comes on to
indicate when service is required. Malfunctions often will
be indicated by the system before any problem is
apparent. This may prevent more serious damage to
your vehicle. This system is also designed to assist your
service technician in correctly diagnosing any
malfunction.
Notice: If you keep driving your vehicle with this
light on, after a while, your emission controls
may not work as well, your fuel economy may not
be as good and your engine may not run as
smoothly. This could lead to costly repairs that may
not be covered by your warranty.
Notice: Modifications made to the engine,
transmission, exhaust, intake or fuel system of your
vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect your vehicle’s emission
controls and may cause this light to come on.
Modifications to these systems could lead to costly
repairs not covered by your warranty. This may
also result in a failure to pass a required Emission
Inspection/Maintenance test.
3-3

If the Light Comes On
This light should come on, as a check to show you it is
working, when the ignition is on and the engine is
not running. If it does not, have it repaired. This light will
also come on if an emission control system malfunction
has been detected on your vehicle. Diagnosis and
service may be required.
You also may be able to correct the emission system
malfunction by considering the following:
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out. A few driving trips should turn the light off.
Are you low on fuel?
As your engine starts to run out of fuel, your engine
may not run as efficiently as designed since small
amounts of air are sucked into the fuel line. The system
can detect this. Adding fuel should correct this
condition. It will take a few driving trips to turn the
light off.
If none of the above steps have made the light turn off,
your dealer can check the vehicle. Your dealer has
the proper test equipment and diagnostic tools to fix any
mechanical or electrical problems that may have
developed.
Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have or
may begin programs to inspect the emission control
equipment on your vehicle. Failure to pass this
inspection could prevent you from getting a vehicle
registration.
Here are some things you need to know in order to help
your vehicle pass an inspection:
Your vehicle will not pass this inspection if the Check
Engine light is on or not working properly.
Your vehicle will not pass this inspection if the OBD
(on-board diagnostic) system determines that critical
emission control systems have not been completely
diagnosed by the system. The vehicle would be
considered not ready for inspection. This can happen if
you have recently replaced your battery or if your
battery has run down. The diagnostic system is
designed to evaluate critical emission control systems
during normal driving. This may take several days
of routine driving. If you have done this and your vehicle
still does not pass the inspection for lack of OBD
system readiness, your GM dealer can prepare the
vehicle for inspection.
3-4

Oil Pressure Gage
The oil pressure gage shows the engine oil pressure in
psi (pounds per square inch) when the engine is
running. Canadian vehicles indicate pressure in kPa
(kilopascals).
Oil pressure may vary under different driving conditions
and oil types. The DURAMAX™ engine may generate
oil pressure in excess of 80 psi (548 kPa) under certain
conditions, especially in cold temperatures. This is a
normal operating range.
{CAUTION:
Do not keep driving if the oil pressure is low. If
you do, your engine can become so hot that it
catches fire. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice: Lack of proper engine oil maintenance may
damage the engine. The repairs would not be
covered by your warranty. Always follow the
maintenance schedule in this manual for changing
engine oil.
United States Canada
3-5

Wait to Start Light
Your diesel engine has a
glow plug system to aid in
starting your vehicle.
An instrument panel wait to start indicator light shows
that the system is functioning properly and tells you
when the engine is ready to be started.
For more information, see Starting Your Diesel Engine
on page 2-2.
Fuel Gage
When the ignition is on,
the fuel gage shows you
approximately how
much fuel you have left in
your tank.
The gage will first indicate E (Empty) before you are out
of fuel, but you should get more fuel as soon as
possible.
3-6

Listed are four situations you may experience with your
fuel gage:
•At the gas station, the fuel pump shuts off before
the gage reads F (Full).
•It takes a little more or less fuel to fill up than the
fuel gage indicated. For example, the gage may
have indicated the tank was half full, but it actually
took a little more or less than half the tank’s
capacity to fill the tank.
•The gage moves a little when you turn a corner or
speed up.
•The gage doesn’t go back to E (Empty) when you
turn off the ignition.
None of these indicate a problem with the fuel gage.
For information on how to fill your fuel tank, see Filling
Your Tank on page 5-12.
For your fuel tank capacity, see “Fuel, Tank Capacity” in
the owner’s manual index.
Your vehicle also has a fuel cooler. To clean,
powerwash the bottom of the vehicle.
Driver Information Center (DIC)
The Driver Information Center (DIC) is located on the
instrument panel cluster above the steering wheel. The
DIC comes on when the ignition is on. After a short
delay the DIC will display the current driver and
the information that was last displayed before the engine
was last turned off.
If a problem is detected, a warning message will appear
on the display. Pressing the select button on the DIC
steering wheel buttons, or the trip odometer reset stem
for vehicles without DIC steering wheel buttons, will
acknowledge any current warning or service messages.
Two messages that your DURAMAX™ diesel may
show are:
ELEVATED IDLE DISABLED
On diesel engines, this message will appear when the
elevated idle/exhaust restrictor feature has been
turned off. For more information on the elevated
idle/exhaust restrictor feature, see Starting Your Diesel
Engine on page 2-2.
3-7

ELEVATED IDLE ENABLED
On diesel engines, this message will appear when the
elevated idle/exhaust restrictor feature has been
turned on. For more information on the elevated
idle/exhaust restrictor feature, see Starting Your Diesel
Engine on page 2-2.
REDUCED ENGINE POWER
On diesel engines, a computer monitors the operation of
the electric accelerator. If the REDUCED ENGINE
POWER message comes on while you are driving, the
computer is indicating that your vehicle has a problem.
You should take your vehicle in for service soon.
WATER IN FUEL
This message will come on to warn you if there is water
in the diesel fuel system. For more information on
how this message works, see Diesel Fuel Requirements
and Fuel System on page 5-2.
3-8

Diesel Fuel Requirements and Fuel System .......5-2
Diesel Engine Fuel .........................................5-2
What Fuel to Use ...........................................5-3
Very Cold Weather Operation ...........................5-5
Water in Fuel .................................................5-5
Water in Fuel Light Chart ................................5-6
Running Out of Fuel .....................................5-10
Fuel Filter Replacement .................................5-10
Filling Your Tank ..........................................5-12
Filling a Portable Fuel Container .....................5-13
Checking Things Under the Hood ....................5-14
Engine Compartment Overview .......................5-14
Engine Oil ...................................................5-16
Engine Air Cleaner/Filter ................................5-21
Automatic Transmission Fluid .........................5-23
Engine Coolant .............................................5-26
Coolant Surge Tank Pressure Cap ..................5-29
Engine Overheating .......................................5-30
Cooling System ............................................5-32
Capacities and Specifications ..........................5-38
Specification Charts ......................................5-38
Section 5 Service and Appearance Care
5-1

Diesel Fuel Requirements and
Fuel System
Some states and provinces have restrictions on the
purchase of diesel fuel for light-duty vehicles and require
you to buy permits or pay special taxes. Some of
these restrictions apply only to residents, and others
apply to both residents and visitors. These restrictions
can change. To learn the current restrictions in any
state or province, contact your auto club, the police or
other officials.
Diesel Engine Fuel
Notice: Diesel fuel or fuel additives not
recommended in this manual could damage your
fuel system and engine. Your warranty would
not cover this damage. And:
•Diesel fuel that has been mixed with engine oil
or automatic transmission fluid could damage
your engine and emission controls.
•Aftermarket diesel fuel additives are not tested
by General Motors. Some additives, particularly
those which contain alcohol or water
emulsifiers, may damage your fuel system. If
you believe that unique circumstances call for a
fuel additive to be used, consult your dealer
for advice.
•If you ever run out of diesel fuel, it can be
difficult to restart your engine. To avoid all this,
never let your tank get empty.
If you run out of fuel, Running Out of Fuel on page 5-10,
tells you how to restart your engine.
5-2