Service............................................................5-3
Doing Your Own Service Work.........................5-4
Two Safety Cautions about Engine Fan
Breakage...................................................5-5
Fuel................................................................5-6
Gasoline Octane............................................5-6
Gasoline Specifications....................................5-6
Additives.......................................................5-7
Diesel Engine Fuel.........................................5-8
What Fuel to Use...........................................5-8
Very Cold Weather Operation.........................5-10
Water in Fuel...............................................5-10
Running Out of Fuel.....................................5-15
Fuel Filter Replacement.................................5-15
Fuels in Foreign Countries.............................5-16
Filling Your Tank..........................................5-17
Filling a Portable Fuel Container.....................5-18
Checking Things Under the Hood....................5-18
Hood Latches...............................................5-19
Engine Oil (Caterpillar
®Diesel Engine).............5-20
Engine Oil (Gasoline Engine)..........................5-20
Engine Oil (DURAMAX™ Diesel).....................5-25
Engine Air Cleaner/Filter................................5-30
Automatic Transmission Fluid.........................5-31
Manual Transmission Fluid.............................5-32Engine Coolant (Gas and
DURAMAX™ engines)................................5-32
Engine Coolant (Caterpillar
®Diesel Engines).....5-35
Coolant Surge Tank Pressure Cap..................5-35
Engine Overheating.......................................5-36
Cooling System............................................5-38
Engine Fan Noise.........................................5-43
Power Steering Fluid.....................................5-43
Windshield Washer Fluid................................5-44
Brakes........................................................5-46
Battery........................................................5-55
Jump Starting...............................................5-56
Rear Axle.......................................................5-61
Rear Axle Shift Motor....................................5-61
Noise Control System.....................................5-62
Tampering with Noise Control System
Prohibited.................................................5-62
Bulb Replacement..........................................5-63
Replacement Bulbs.......................................5-63
Windshield Wiper Blade Replacement..............5-63
Other Service Items........................................5-64
Fuel Filter....................................................5-64
Primary Fuel Filter and Water Separator..........5-65
Secondary Fuel Filter and Water
Separator/Heater.......................................5-66
Section 5 Service and Appearance Care
5-1
5. Then replace the
pressure cap. Be sure
the pressure cap is
hand-tight and
fully seated.
Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the clutch is not fully engaged. This improves
fuel economy and reduces fan noise. Under heavy
vehicle loading, trailer towing and/or high outside
temperatures, the fan speed increases when the clutch
engages. So you may hear an increase in fan noise.
This is normal and should not be mistaken as thetransmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
Power Steering Fluid
See your Maintenance Schedule for when to check your
power steering fluid.
How To Check Power Steering Fluid
Check your power steering fluid only when the engine is
warm. If the engine isn’t warm, you probably won’t
get an accurate reading.
If the fluid level is between the MIN and MAX marks,
you have enough. If you need fluid, add only enough of
the proper fluid to bring it in between the MIN and
MAX marks.
5-43
If your power steering fluid level is low, this can cause
the brake or service brake soon warning lights to
come on. In addition, the steering effort and emergency
brake distance could increase.
If either light remains on after you have added power
steering fluid to the proper level, then shut off the engine
for 10 seconds. This should reset the brake warning
lights. If one or both lights stay on though, see
“Hydraulic Brake System Warning Lights” underBrake
System Warning Light on page 3-31for more
information.
What to Use
To determine what kind of fluid to use, seePart C:
Recommended Fluids and Lubricants on page 6-29.
Notice:When adding power steering uid or
making a complete uid change, always use the
proper uid. Failure to use the proper uid can
cause leaks and damage hoses and seals.
Windshield Washer Fluid
What to Use
When you need windshield washer fluid, be sure to read
the manufacturer’s instructions before use. If you will
be operating your vehicle in an area where the
temperature may fall below freezing, use a fluid that has
sufficient protection against freezing.
Adding Washer Fluid
Your vehicle has a low
washer fluid light that lets
you know when to add
washer fluid.
5-44
Part Engine
(RPO Code)GM Part
NumberACDelco®Part
NumberOther Part
Numbers
Engine Air Cleaner/Filter
6.6L (LB7/LLY) (C4/C5 Models)
6.6L (LB7/LLY) (C6/C7/C8 Models)
7.2L (LG5)
7.8L (LG4) (C4/C5 Models)
7.8 L (LG4) (C6/C7/C8 Models)
8.1L (L18)88937527
88937548***
—
8837527
88937548***
25313349—
—
—
—
—
A1518C—
—
Donaldson P522606
—
—
—
Engine Oil Filter
6.6L (LB7/LLY)
7.2L (LG5)
7.8L (LG4)
8.1L (L18)88917036
—
94392475
89028862PF2232
—
—
PF454—
CAT 1R0739
—
—
Fuel Filter
6.6L (LB7/LLY)
7.2L (LG5)
7.8L (LG4)
8.1L (L18)97256734
—
94392474
——
915 Primary**
—
GF626*—
—
—
—
Power Steering Fluid Filter
6.6L (LB7/LLY)
7.2L (LG5)
7.8L (LG4)
8.1L (L18)88892858
88892858
88892858
88892858—
—
—
——
—
—
—
5-101
Part C: Recommended Fluids and
Lubricants
Fluids and lubricants identified below by name, part
number or specification may be obtained from your
dealer.
Usage Fluid/Lubricant
Engine Oil
(Gasoline
Engine)Engine oil which meets GM
Standard GM6094M and displays
the American Petroleum Institute
Certified for Gasoline Engines
starburst symbol. To determine the
proper viscosity for your vehicle’s
engine, see “Engine Oil” in the
Index.
Engine Oil
(DURAMAX™
Diesel Engine)Engine oil with the letters CI-4 or
CH-4 is best for your vehicle. The
CI-4 or CH-4 designation may
appear either alone or in
combination with other API
designations, such as API CI-4/SL.
These letters show American
Petroleum Institute levels of quality.
To determine the preferred viscosity
for your vehicle’s diesel engine, see
“Engine Oil” in the Index.
Usage Fluid/Lubricant
Engine Oil
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine oil
recommendations.
Engine Coolant
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine
coolant recommendations.
Engine Coolant
(Gasoline
Engine &
DURAMAX™
Diesel)50/50 mixture of clean, drinkable
water and use only
DEX-COOL
®Coolant. See “Engine
Coolant” in the Index.
Hydraulic Brake
SystemDelco Supreme 11 Brake Fluid or
equivalent DOT-3 brake fluid.
Windshield
Washer SolventGM Optikleen
®Washer Solvent.
Clutch Bearing
LubricantClutch Bearing Lubricant (GM Part
No. 12378484 or equivalent NLGI #3
consistency).
Exhaust Brake
Ball Joint Cap
LubricantHigh-Temperature Grease (GM Part
No. U.S. 1051344, in Canada
903037) or NLGI #3 consistency.
Power Steering
SystemDEXRON
®-III Automatic
Transmission Fluid.
6-29
Exhaust Restrictor (Diesel Engines)...................2-18
Exhaust System Check....................................6-27
Express-Down Feature.....................................2-10
Extender, Safety Belt.......................................1-26
Exterior Lamps...............................................3-13
F
Filter
Engine Air Cleaner......................................5-30
Filter Minder Gage..........................................3-44
Finding a Station............................3-46, 3-49, 3-53
Finish Care....................................................5-80
Finish Damage...............................................5-83
Fixed Mast Antenna........................................3-59
Flat Tire........................................................5-75
Flat Tire, Changing.........................................5-76
Fluid
Automatic Transmission................................5-31
Manual Transmission....................................5-32
Power Steering...........................................5-43
Windshield Washer......................................5-44
Fluid Leaks Check..........................................6-28
FM ...............................................................3-57
Folding the Rear Seat (Crew Cab).................... 1-7
Footnotes......................................................6-19
Fore-and-Aft Adjustment.................................... 1-4Four-Wheel and Six-Wheel Drum Brakes
(Air Only)...................................................5-49
Four-Wheel Disc Brakes
(Hydraulic Only)..........................................5-49
Front Wheel Bearings with Oil-Filled Hubs..........5-67
Fuel............................................................... 5-6
Additives...................................................... 5-7
Diesel Engine Fuel........................................ 5-8
Filling a Portable Fuel Container....................5-18
Filling Your Tank..........................................5-17
Filter..........................................................5-64
Filter Replacement.......................................5-15
Fuels in Foreign Countries............................5-16
Gage.........................................................3-42
Gasoline Octane........................................... 5-6
Gasoline Specifications.................................. 5-6
Primary Filter and Water Separator................5-65
Running Out of Fuel....................................5-15
Secondary Filter and Water Separator/Heater....5-66
Very Cold Weather Operation........................5-10
Water in Fuel..............................................5-10
Water in Warning Light.................................3-43
What Fuel to Use.......................................... 5-8
Fuel Filter (Diesel Engines)..............................5-65
Fuel Filter (Gasoline Engines)...........................5-64
Fuel Priming..................................................5-13
Fuses
Fuses and Circuit Breakers...........................5-87
Windshield Wiper.........................................5-87
6
G
Gage
Air Pressure...............................................3-44
Check Gages Warning Light..........................3-42
Engine Coolant Temperature.........................3-35
Filter Minder...............................................3-44
Fuel..........................................................3-42
Hourmeter..................................................3-45
Oil Pressure...............................................3-37
Speedometer..............................................3-25
Tachometer.................................................3-26
Transmission Temperature.............................3-40
Voltmeter Gage...........................................3-30
Gasoline
Octane........................................................ 5-6
Specifications............................................... 5-6
Gasoline Engine, Starting.................................2-12
Gasoline Engine Warm-Up...............................2-14
Glass, Mirrors, Lamps and/or Reflectors
Condition Check..........................................6-27
H
Hazard Warning Flashers................................... 3-5
Headlamp High/Low-Beam Changer.................... 3-8
Headlamp Wiring............................................5-86Headlamps On Reminder.................................3-13
Heavy-Duty Trailer Wiring Package....................4-35
Height Adjustment............................................. 1-6
High Idle System (Caterpillar
®Diesel and
Gasoline Engines).......................................2-16
Highway Hypnosis...........................................4-23
Hill and Mountain Roads..................................4-23
Hood
Checking Things Under................................5-18
Latches......................................................5-19
Hood Latches Check.......................................6-28
Horn............................................................... 3-6
Hourmeter Gage.............................................3-45
How to Add Coolant to the Coolant
Surge Tank.................................................5-39
How to Add Fluid............................................5-32
How to Check................................................5-69
How to Check and What to Use...............5-31, 5-32
How to Check Fluid........................................5-61
How to Check Lubricant...................................5-61
How To Check Power Steering Fluid..................5-43
How to Inspect the Engine Air Cleaner/Filter.......5-30
How to Use This Manual...................................... ii
How to Wear Safety Belts Properly...................1-13
Hydraulic Brake System
Warning Lights............................................3-32
Hydraulic Brake Systems................................... 4-6
Hydraulic Brakes.............................................2-33
Hydroplaning..................................................4-20
7
P
Parking.........................................................2-33
Brake Warning Light....................................3-34
Over Things That Burn.................................2-37
Parking Brake Check.......................................6-25
Part A - Scheduled Maintenance Services............ 6-4
Part B - Owner Checks and Services................6-24
Part C - Recommended Fluids and Lubricants....6-29
Part D - Maintenance Record...........................6-31
Passing.........................................................4-14
Playing a Cassette..........................................3-50
Playing a Compact Disc...................................3-55
Playing the Radio...........................3-46, 3-48, 3-53
Power
Accessory Outlets........................................3-17
Door Locks.................................................. 2-7
Electrical System.........................................5-87
Reduced Engine Light..................................3-41
Steering Fluid.............................................5-43
Windows...................................................... 2-9
Power Steering...............................................4-12
Propshaft Park Brake Burnish Procedure............2-34
Q
Questions and Answers About Safety Belts.........1-12
R
Radio Messages.............................3-48, 3-50, 3-55
Radios..........................................................3-45
AM-FM Radio.............................................3-46
Care of Your Cassette Tape Player................3-57
Care of Your CD Player...............................3-59
Care of Your CDs........................................3-59
Radio with Cassette.....................................3-48
Radio with CD............................................3-53
Setting the Time..........................................3-45
Theft-Deterrent............................................3-57
Understanding Reception..............................3-57
Range Inhibit Warning Indicator........................3-31
Reading Lamps..............................................3-16
Rear Axle......................................................5-61
Differential Lock Control...............................4-10
Shift Motor.................................................5-61
Two-Speed Electric Shift Control....................2-26
Rear Heating System......................................3-23
Rear Seat Operation......................................... 1-7
11