
Low Oil Level Light
This light should come on
as a check, when you start
your engine. If the light
fails to come on, have it
repaired as soon as
possible so you will be
aware when the oil level
is low.
If this light comes on and stays on, it means your
engine is low on oil. You need to check the oil level
right away. SeeEngine Oil (Caterpillar
®Diesel Engine)
on page 5-22orEngine Oil (DURAMAX®Diesel) on
page 5-22orEngine Oil (Gasoline Engine) on page 5-26
for further information.
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.
Change Engine Oil Light
The change engine oil light
should come on briefly as
a bulb check when you
start the engine. If the light
does not come on, have
it serviced.
If the change engine oil light comes on and stays on
after you start the engine, have the oil changed.
For additional information on when to change engine oil
for gasoline engines or DURAMAX
®diesel engines,
seeEngine Oil (Caterpillar®Diesel Engine) on page 5-22
orEngine Oil (DURAMAX®Diesel) on page 5-22or
Engine Oil (Gasoline Engine) on page 5-26and
Scheduled Maintenance on page 6-5. To reset the
change engine oil light, seeEngine Oil Life System
(Gasoline Engine) on page 5-29orEngine Oil Life
System (DURAMAX
®Diesel) on page 5-31orEngine
Oil Life System (Caterpillar®Diesel Engine) on
page 5-32.
3-38

If your vehicle has dual fuel tanks, the reading on the
gage is the total fuel left in both tanks.
Here are four concerns of some operators. None of
these shows a problem with your fuel gage:
•The gage moves a little when you turn a corner or
speed up.
•The gage does not go back to empty when you turn
off the ignition.
•At the gas station, the pump shuts off before the
gage reads full.
•It takes a little more or less fuel to fill up than the
gage indicated.
If you have a Caterpillar
®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
Water in Fuel Warning Light
If your vehicle has the 6.6L
or 7.8L DURAMAX®diesel
engine, this light will
come on to warn you that
there is water in the
fuel system.
For more information on how this light works, seeWater
in Fuel on page 5-10.
Air Filter Restriction Indicator
If your vehicle has this
feature, the gage is
located above the
switchbank in the center of
the instrument panel. It
monitors the engine
air filter.
As the filter gets dirty, the yellow indicator will begin to
rise. When it reaches 25 inches of vacuum on the
scale, the filter should be replaced.
After replacing the filter, reset the gage by pressing in
the yellow reset button at the bottom of the gage.
If you have a Caterpillar
®diesel engine, also see your
Caterpillar®Operation & Maintenance Manual.
3-43

Other Service Items........................................5-66
Fuel Filter....................................................5-66
Primary Fuel Filter and Water Separator..........5-67
Secondary Fuel Filter and Water Separator/
Heater (Caterpillar
®Diesel)..........................5-68
Automatic Ether Injection System
(Caterpillar
®Diesel)....................................5-68
Front Wheel Bearings with Oil-Filled Hubs........5-69
Air Conditioning System.................................5-70
Tires..............................................................5-70
Inflation - Tire Pressure.................................5-71
Wheel Loading.............................................5-71
Dual Tire Operation.......................................5-72
When It Is Time for New Tires.......................5-72
Wheel Alignment and Tire Balance..................5-73
Tightening the Wheel Nuts.............................5-73
Wheel Replacement......................................5-77
If a Tire Goes Flat........................................5-78
Appearance Care............................................5-79
Cleaning the Inside of Your Vehicle.................5-80
Fabric/Carpet...............................................5-81
Instrument Panel, Vinyl, and Other
Plastic Surfaces........................................5-82
Care of Safety Belts......................................5-82
Weatherstrips...............................................5-82Washing Your Vehicle...................................5-83
Cleaning Exterior Lamps/Lenses.....................5-83
Finish Care..................................................5-83
Windshield and Wiper Blades.........................5-84
Aluminum or Chrome-Plated Wheels................5-84
Tires...........................................................5-85
Sheet Metal Damage.....................................5-85
Finish Damage.............................................5-85
Underbody Maintenance................................5-85
Chemical Paint Spotting.................................5-85
Vehicle Identi cation......................................5-87
Vehicle Identification Number (VIN).................5-87
Service Statement.........................................5-87
Service Parts Identification Label.....................5-88
Electrical System............................................5-88
Add-On Electrical Equipment..........................5-88
Headlamp Wiring..........................................5-88
Windshield Wiper Fuses................................5-88
Fusible Links................................................5-89
Power Windows and Other Power Options.......5-89
Fuses and Circuit Breakers............................5-89
Instrument Panel Fuse Block..........................5-89
Underhood Fuse Block..................................5-92
Capacities and Speci cations..........................5-95
Normal Maintenance Replacement Parts.........5-100
Section 5 Service and Appearance Care
5-2

Doing Your Own Service Work
If you want to do some of your own service work, you
will want to use the proper service manual. It tells
you much more about how to service your vehicle than
this manual can. To order the proper service manual,
seeService Publications Ordering Information on
page 7-8.
Your vehicle has an airbag system. Before attempting
to do your own service work, seeServicing Your
Airbag-Equipped Vehicle on page 1-59.
You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. SeePart D: Maintenance Record on page 6-34.{CAUTION:
You can be injured and your vehicle could be
damaged if you try to do service work on a
vehicle without knowing enough about it.
Be sure you have sufficient knowledge,
experience, the proper replacement parts,
and tools before you attempt any vehicle
maintenance task.
Be sure to use the proper nuts, bolts, and
other fasteners. English and metric
fasteners can be easily confused. If you
use the wrong fasteners, parts can later
break or fall off. You could be hurt.
5-4

Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area to contribute to clean air. General Motors
recommends that you use these gasolines, particularly if
they comply with the specifications described earlier.
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage would not be covered under
your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors
does not recommend the use of such gasolines.
Fuels containing MMT can reduce the life of spark plugs
and the performance of the emission control system
may be affected. The malfunction indicator lamp
may turn on. If this occurs, return to your authorized
GM dealer for service.Diesel Engine Fuel
For the Caterpillar®diesel, see the Caterpillar®
Operation & Maintenance Manual for information
concerning fuel usage.
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 uid 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 emulsi ers,
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 gasoline is ever accidentally added to the fuel
tank, to avoid severe engine damage, do not run the
engine until the fuel tank can be drained.
If you run out of fuel,Running Out of Fuel on page 5-15
tells you how to restart your engine.
5-7

5. Remove the fuel-resistant container and properly
dispose of the contaminated fuel. To find out how to
properly dispose of contaminated diesel fuel,
seeEngine Oil (Caterpillar
®Diesel Engine) on
page 5-22orEngine Oil (DURAMAX®Diesel)
on page 5-22orEngine Oil (Gasoline Engine) on
page 5-26.
6. Install the fuel cap.
7. Start the engine and let it run for a few minutes.
If the engine stalls, the fuel system may need to be
primed. While draining the water from the fuel filter,
air may enter the fuel system. If air has entered the
fuel system the fuel system will need to be primed.
If the water-in-fuel light comes on again after driving a
short distance or the engine runs rough or stalls, a large
amount of water has probably been pumped into the
fuel tank. The fuel tank should be purged.
Fuel Priming
If your vehicle has a Caterpillar®diesel engine, see the
Caterpillar®Diesel Engine Operation and Maintenance
Manual provided with your vehicle.
If your vehicle has a DURAMAX
®diesel engine, in order
for the fuel system to work properly, the fuel lines
must be full of fuel and contain no air. If air gets into the
fuel lines, it will be necessary to prime the fuel lines
to eliminate air before operating the vehicle.
Air can get into the fuel lines if any of the following happen:
•The vehicle runs out of fuel.
•The fuel filter is removed for servicing or
replacement.
•The fuel lines are removed or disconnected for
servicing.
•The fuel filter water drain valve is opened while the
engine is running.
If one or more of the above occurred, it is very likely that
air has entered your fuel system and that you will need to
prime the fuel system before operating the vehicle.
Air in the fuel lines will not harm the engine or the
vehicle. However, the engine may not be able to start
until the fuel system is primed and the air is removed.
5-12

Engine Oil
(Caterpillar
®Diesel Engine)
See your Caterpillar®Operation & Maintenance Manual
for information on oil quality and viscosities as well
as the temperature range chart.
Engine Oil (DURAMAX®Diesel)
Checking Engine Oil
It is a good idea to check your engine oil level every
time you get fuel.
The engine oil dipstick is
located in the engine
compartment on the
driver’s side of the vehicle.In order to get an accurate reading, the engine should
be at normal operating temperature, so that the oil
is warm, and the vehicle must be on level ground.
1. If the engine is at normal operating temperature and
the oil is warm, turn off the engine and allow at
least five minutes for the oil to drain back into the
oil pan. If you do not do this, the oil dipstick
might not show the actual level.
If the engine has not been run long enough to bring
it up to normal operating temperature and the oil
is cool, turn off the engine and allow 30 minutes for
the oil to drain back into the oil pan. If you do
not do this, the oil dipstick might not show the
actual level.
2. Pull out the dipstick and clean it with a paper towel
or a cloth, then push it back in all the way.
3. Remove the dipstick again, keeping the tip down,
and check the oil level.
5-22

•SAE 15W-40
As shown in the viscosity chart, SAE 15W-40 is
best for your vehicle. However, you can use
SAE 10W-30 at temperatures above 0°F (−18°C).
When it is very cold, below 0°F (−18°C), you should
use SAE 5W-40 to improve cold starting.
These numbers on the oil container show its
viscosity, or thickness. Do not use other viscosity
oils such as SAE 10W-40 or SAE 20W-50.
This doughnut-shaped
logo (symbol) is used on
most oil containers to
help you select the correct
oil. It means that the oil
has been certified by
the American Petroleum
Institute.
You should look for this on the oil container, and use
onlythose oils that display this logo.
GM Goodwrench
®oil of the recommended viscosity
grades meets all the requirements for your vehicle.
Engine Oil Additives
Do not add anything to your oil. The recommended oils
with the API service symbol are all you will need for
good performance and engine protection.
When to Change Engine Oil (Vehicles
Without the Engine Oil Life System)
If you have the 6.6L V8 (LLY) Engine: Change engine
oil and filter every 15,000 miles (24 000 km), or
every 12 months, or every 750 hours of engine
operation, whichever occurs first. If you have the
7.8L V6 (LG4) Engine: Change engine oil and filter
every 12,000 miles (20 000 km), or every 12 months,
or every 600 hours of engine operation, whichever
occurs first. SeeScheduled Maintenance on page 6-5.
5-25