Vehicle Symbol Chart
Here are some additional symbols that may be found on
the vehicle and what they mean. For more information
on the symbol, refer to the index.
9:Airbag Readiness Light
#:Air Conditioning
!:Antilock Brake System (ABS)
g:Audio Steering Wheel Controls or OnStar®
$:Brake System Warning Light
":Charging System
I:Cruise Control
B:Engine Coolant Temperature
O:Exterior Lamps
#:Fog Lamps
.:Fuel Gage
+:Fuses
i:Headlamp High/Low-Beam Changer
j:LATCH System Child Restraints
*:Malfunction Indicator Lamp
::Oil Pressure
}:Power
/:Remote Vehicle Start
>:Safety Belt Reminders
7:Tire Pressure Monitor
F:Traction Control
M:Windshield Washer Fluid
iv
Service............................................................5-3
Accessories and Modifications..........................5-3
California Proposition 65 Warning.....................5-4
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-5
Engine Fan Breakage.....................................5-6
Fuel................................................................5-6
Gasoline Octane............................................5-6
Gasoline Specifications....................................5-7
Additives.......................................................5-7
Diesel Engine Fuel.........................................5-8
What Fuel to Use...........................................5-8
Very Cold Weather Operation.........................5-11
Water in Fuel...............................................5-11
Running Out of Fuel.....................................5-17
Fuel Filter Replacement.................................5-18
Fuels in Foreign Countries.............................5-19
Filling the Tank............................................5-20
Filling a Portable Fuel Container.....................5-22
Checking Things Under the Hood....................5-22
Hood Latches...............................................5-23
Engine Oil (DURAMAX Diesel Engine).............5-24
Engine Oil (Caterpillar Diesel Engine)..............5-27
Engine Oil (Isuzu Diesel Engine).....................5-28
Engine Oil (Gasoline Engine)..........................5-32
Engine Oil Life System (Gasoline Engine)........5-35Engine Oil Life System (DURAMAX/Isuzu
Diesel Engines).........................................5-36
Engine Oil Life System (Caterpillar
Diesel Engine)..........................................5-38
Engine Air Cleaner/Filter................................5-38
Automatic Transmission Fluid.........................5-42
Manual Transmission Fluid.............................5-42
Cooling System............................................5-43
Engine Coolant (Caterpillar Diesel Engines)......5-47
Coolant Surge Tank Pressure Cap..................5-47
Engine Overheating.......................................5-48
Engine Fan Noise.........................................5-49
Power Steering Fluid.....................................5-49
Windshield Washer Fluid................................5-50
Brakes........................................................5-52
Battery........................................................5-61
Jump Starting...............................................5-62
Rear Axle.......................................................5-67
Rear Axle Shift Motor....................................5-68
Four-Wheel Drive............................................5-68
Front Axle......................................................5-69
Noise Control System.....................................5-70
Tampering with Noise Control System
Prohibited.................................................5-70
Bulb Replacement..........................................5-71
Section 5 Service and Appearance Care
5-1
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. In heavy traffic, let the engine idle in N (Neutral)
while stopped. If it is safe to do so, pull off the
road, shift to P (Park) or N (Neutral) and let
the engine idle.
2. Turn on your heater to full hot at the highest fan
speed and open the windows as necessary.
3. If climbing a hill, downshift to raise engine and fan
speeds.
If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning does not come back on, you can drive
normally.
If the warning continues and you have not stopped, pull
over, stop, and park your vehicle right away.
If there is still no sign of steam, you can push down the
accelerator until the engine speed is about twice as
fast as normal idle speed for at least three minutes while
you are parked. If you still have the warning, turn off
the engine and get everyone out of the vehicle until it
cools down.
You may decide not to lift the hood but to get service
help right away.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 the
transmission 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
SeeScheduled Maintenance on page 6-5to determine
when to check your power steering fluid.
5-49
How To Check Power Steering Fluid
Check your power steering fluid only when the engine is
warm. If the engine is not warm, you probably will not
get an accurate reading.
If the fluid level is between the MIN (Minimum) and
MAX (Maximum) 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.
If your power steering fluid level is low, this can cause
the brake or service brakes 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, 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 6-31.
Notice:When adding power steering fluid or
making a complete fluid change, always use the
proper fluid. Failure to use the proper fluid 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.
5-50
Part GM Part Number ACDelco Part Number
Fuel Filter
6.6L V8 98017645 TP1298B
7.2L L6 — 1R-0751
2
Isuzu 6H 98026037 —
8.1L V8 (C4/C5 with NG6/NK1 or U-Haul) 15807649 —
8.1L V8 (C4/C5 with all other fuel tanks) 10376257 —
8.1L V8 (All C6/C7/C8) 10370247 —
Power Steering Fluid Filter 88892858 —
Secondary Fuel Filter
6.6L V8 — —
7.2L L6 (NWB/KUR) 25982639 S3229
3
Isuzu 6H (NWB) 15618921 S32023
Isuzu 6H (KUK) 88983117 TP1519
8.1L V8 (K28 and standard U-Haul) 25014476 TP1247
Spark Plugs
6.6L V8 — —
7.2L L6 — —
Isuzu 6H — —
8.1L V8 12578277 41-983
1Optional air filter (GM Part No. 88937548 AC Delco No. A2035C) for C6/C7/C8 Models. Fits inside standard size
filter (GM Part No. 88937525 AC Delco No. A2031C) listed previously.
2Caterpillar®part number.3Racor part number.
See the Allison Transmission Operator’s Manual in your vehicle for external filter part numbers and information.
5-109
Part C: Recommended Fluids and
Lubricants
Fluids and lubricants identified below by name, part
number, or specification can be obtained from your
dealer/retailer.
Usage Fluid/Lubricant
Engine Oil
(Gasoline
Engine)Engine oil which meets GM Standard
GM6094M and displays the
American Petroleum Institute (API)
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
®/
Isuzu Diesel
Engines)Engine oils with the letters CJ-4 are
required for your vehicle. The CJ-4
designation can appear either alone
or in combination with other
American Petroleum Institute (API)
designations, such as API CJ-4/SL.
These letters show API levels of
quality. To determine the preferred
viscosity for your vehicle’s diesel
engine, see “Engine Oil” in the Index.
Engine Oil
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine oil
recommendations.
Usage Fluid/Lubricant
Engine Coolant
(Caterpillar
®
Diesel Engine)See the Caterpillar
®Operation &
Maintenance Manual for engine
coolant recommendations.
Engine Coolant
(Gasoline
Engine &
DURAMAX
®/
Isuzu Diesel
Engines)50/50 mixture of clean, drinkable
water and use only DEX-COOL
®
Coolant. SeeEngine Coolant
(Caterpillar Diesel Engines) on
page 5-47.
Hydraulic Brake
SystemDelco
®Supreme 11 Brake Fluid or
equivalent DOT-3 brake fluid.
Windshield
Washer SolventOptikleen
®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
®-VI Automatic
Transmission Fluid.
Manual
TransmissionSynthetic Manual Transmission Fluid
(GM Part No. U.S. 88861952,
in Canada 88861953).
Automatic
TransmissionSee the Allison Transmission
®
Operator’s Manual for correct
transmission fluid.
6-31
Engine (cont.)
Overheating................................................5-48
Overspeed Warning Light..............................3-40
Reduced Power Light...................................3-42
Shutdown Warning Light...............................3-40
Speed Limiter.............................................3-25
Starter Over-Crank Protection........................2-12
Starting Diesel............................................2-14
Starting the Gasoline...................................2-12
Entry Lighting.................................................3-17
Event Data Recorders.....................................7-12
Exhaust Brake Indicator Light...........................3-41
Exhaust Restrictor...........................................2-22
Extender, Safety Belt.......................................1-28
Exterior Lamps...............................................3-14
F
Filter
Engine Air Cleaner......................................5-38
Filter Minder Gage..........................................3-46
Finish Damage...............................................5-93
Fixed Mast Antenna........................................3-58
Flashers, Hazard Warning.................................. 3-6
Flat Tire........................................................5-85
Fluid
Automatic Transmission................................5-42
Power Steering...........................................5-49
Windshield Washer......................................5-50
Four-Wheel Drive....................................2-30, 5-68Front Axle......................................................5-69
Front Wheel Bearings with
Oil-Filled Hubs............................................5-75
Fuel............................................................... 5-6
Additives...................................................... 5-7
Change Filter Warning Light..........................3-45
Diesel Engine Fuel........................................ 5-8
Driving for Better Economy............................. 4-2
Filling a Portable Fuel Container....................5-22
Filling the Tank...........................................5-20
Filter..........................................................5-72
Filter Replacement.......................................5-18
Fuels in Foreign Countries............................5-19
Gage .........................................................3-44
Gasoline Octane........................................... 5-6
Gasoline Specifications.................................. 5-7
Primary Filter and Water Separator................5-73
Running Out of Fuel....................................5-17
Secondary Filter and Water
Separator/Heater......................................5-74
Very Cold Weather Operation........................5-11
Water in Fuel..............................................5-11
Water in Warning Light.................................3-45
What Fuel to Use.......................................... 5-8
Fuses
Fuses and Circuit Breakers...........................5-96
Instrument Panel Fuse Block.........................5-96
Underhood Fuse Block.................................5-99
Windshield Wiper.........................................5-95
5
Outside
Convex Mirrors............................................2-52
Heated Mirrors............................................2-52
Manual Mirrors............................................2-51
Power Mirrors.............................................2-51
Overspeed Warning Light.................................3-40
P
Paint, Damage...............................................5-93
Park Brake............................................2-38, 2-41
Parking.........................................................2-35
Brake Burnish Procedure..............................2-43
Over Things That Burn.................................2-44
Two-Speed Rear Axle..................................2-36
Part A - Scheduled Maintenance Services............ 6-4
Part B - Owner Checks and Services................6-26
PartC-Recommended Fluids and
Lubricants..................................................6-31
PartD-Maintenance Record...........................6-33
Passing.........................................................4-11
Perchlorate Materials Requirements,
California..................................................... 5-4
Power
Door Locks.................................................. 2-7
Electrical System.........................................5-96
Reduced Engine Light..................................3-42
Steering Fluid.............................................5-49
Windows...................................................... 2-9
Power Take-Off Light.......................................3-43Power Take-Off (PTO).....................................2-30
Privacy..........................................................7-11
Event Data Recorders..................................7-12
Navigation System.......................................7-13
OnStar.......................................................7-13
Radio Frequency Identification.......................7-13
R
Radio Frequency Identification (RFID),
Privacy......................................................7-13
Radio(s)........................................................3-49
Radios
Reception...................................................3-58
Setting the Clock.........................................3-48
Theft-Deterrent............................................3-57
Range Inhibit Warning Indicator........................3-31
Reading Lamps..............................................3-17
Rear Axle......................................................5-67
Differential Lock Control................................. 4-7
Shift Motor.................................................5-68
Rear Heating System......................................3-23
Rear Seat Operation.......................................1-10
Rearview Mirrors.............................................2-51
Reduced Engine Power Light............................3-42
Remote Keyless Entry (RKE) System.................. 2-3
Remote Keyless Entry (RKE) System,
Operation..................................................... 2-4
Replacement Parts, Maintenance.....................5-108
9