
If doing some of your own service work, use the proper
service manual. It tells you much more about how to
service the vehicle than this manual can. To order
the proper service manual, seeService Publications
Ordering Information on page 7-16.
This vehicle has an airbag system. Before attempting
to do your own service work, seeServicing Your
Airbag-Equipped Vehicle on page 1-76.
Keep a record with all parts receipts and list the
mileage and the date of any service work performed.
SeeMaintenance Record on page 6-17.
Adding Equipment to the Outside of
the Vehicle
Things added to the outside of the vehicle can affect the
airflow around it. This can cause wind noise and can
affect fuel economy and windshield washer performance.
Check with your dealer/retailer before adding equipment
to the outside of the vehicle.
Fuel
For diesel engine vehicles, see “Diesel Fuel
Requirements and Fuel System” in the DURAMAX®
Diesel manual.
For vehicles with gasoline engines, please read this.
Gasoline
Use of the recommended fuel is an important part of
the proper maintenance of this vehicle. To help keep the
engine clean and maintain optimum vehicle performance,
we recommend the use of gasoline advertised as TOP
TIER Detergent Gasoline.
The 8th digit of the Vehicle Identification Number (VIN)
shows the code letter or number that identifies the
vehicle’s engine. The VIN is at the top left of the
instrument panel. SeeVehicle Identification
Number (VIN) on page 5-104.
If the vehicle has the 5.3L V8 engine (VIN Code 4) and
the N15 flexible fuel option, you can use either regular
unleaded gasoline or ethanol fuel containing up to 85%
ethanol (E85). SeeFuel E85 (85% Ethanol) on page 5-8.
For the 5.3L V8 engine (VIN Code 4) without the N15
option and all other gasoline engines, use only regular
unleaded gasoline.
5-5

Gasoline Octane
Use regular unleaded gasoline with a posted octane
rating of 87 or higher. If the octane rating is less than 87,
you might notice an audible knocking noise when you
drive, commonly referred to as spark knock. If this occurs,
use a gasoline rated at 87 octane or higher as soon as
possible. If you are using gasoline rated at 87 octane or
higher and you hear heavy knocking, the engine needs
service.
Gasoline Speci cations
At a minimum, gasoline should meet ASTM
specification D 4814 in the United States or
CAN/CGSB-3.5 or 3.511 in Canada. Some gasolines
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl (MMT).
We recommend against the use of gasolines containing
MMT. SeeAdditives on page 5-7for additional
information.
California Fuel
If the vehicle is certified to meet California Emissions
Standards, it is designed to operate on fuels that meet
California specifications. See the underhood emission
control label. If this fuel is not available in states adopting
California emissions standards, the vehicle will operate
satisfactorily on fuels meeting federal specifications, but
emission control system performance might be affected.
The malfunction indicator lamp could turn on and the
vehicle might fail a smog-check test. SeeMalfunction
Indicator Lamp on page 3-34. If this occurs, return to your
authorized dealer/retailer for diagnosis. If it is determined
that the condition is caused by the type of fuel used,
repairs might not be covered by the vehicle warranty.
5-6

Filling a Portable Fuel Container
{CAUTION:
Never fill a portable fuel container while it is in
the vehicle. Static electricity discharge from the
container can ignite the fuel vapor. You can be
badly burned and the vehicle damaged if this
occurs. To help avoid injury to you and others:
•Dispense fuel only into approved containers.
•Do not fill a container while it is inside a
vehicle, in a vehicle’s trunk, pickup bed,
or on any surface other than the ground.
•Bring the fill nozzle in contact with the inside
of the fill opening before operating the nozzle.
Contact should be maintained until the filling
is complete.
•Do not smoke while pumping fuel.
•Do not use a cellular phone while
pumping fuel.
Checking Things Under
the Hood
{CAUTION:
Things that burn can get on hot engine or fuel
operated heater (FOH) parts and start a fire.
These include liquids like fuel, oil, coolant, brake
fluid, windshield washer and other fluids, and
plastic or rubber. You or others could be burned.
Be careful not to drop or spill things that will burn
onto a hot engine or fuel operated heater (FOH).
5-12

A. Battery. SeeBattery on page 5-39.
B. Radiator Pressure Cap. SeeRadiator Pressure Cap
on page 5-31.
C. Coolant Recovery Tank. SeeCooling System on
page 5-24.
D. Automatic Transmission Fluid Dipstick.
See “Checking the Fluid Level” underAutomatic
Transmission Fluid on page 5-21.
E. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-15.
F. Engine Oil Dipstick. See “Checking Engine Oil”
underEngine Oil on page 5-15.
G. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-20.
H. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-34.
I. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-36.
J. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-35.Engine Oil
For diesel engine vehicles, see “Engine Oil” in the
DURAMAX®Diesel manual.
Checking Engine Oil
It is a good idea to check the engine oil every time you
get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop.
SeeEngine Compartment Overview on page 5-14
for the location of the engine oil dipstick.
1. Turn off the engine and give the oil several minutes
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 cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
5-15

Engine Oil Additives / Engine Oil
Flushes
Do not add anything to the oil. The recommended
oils with the starburst symbol that meet GM Standard
GM6094M are all you need for good performance and
engine protection.
Engine oil system flushes are not recommended and
could cause engine damage not covered by the vehicle
warranty.
Engine Oil Life System
When to Change Engine Oil
This vehicle has a computer system that lets you
know when to change the engine oil and filter. This is
based on engine revolutions and engine temperature,
and not on mileage. Based on driving conditions, the
mileage at which an oil change will be indicated can vary
considerably. For the oil life system to work properly, you
must reset the system every time the oil is changed.When the system has calculated that oil life has been
diminished, it will indicate that an oil change is necessary.
A CHANGE ENGINE OIL SOON message will come on.
SeeDIC Warnings and Messages on page 3-48. Change
the oil as soon as possible within the next 600 miles
(1 000 km). It is possible that, if you are driving under the
best conditions, the oil life system might not indicate that
an oil change is necessary for over a year. However, the
engine oil and filter must be changed at least once a year
and at this time the system must be reset. Your dealer/
retailer has trained service people who will perform this
work using genuine parts and reset the system. It is also
important to check the oil regularly and keep it at the
proper level.
If the system is ever reset accidentally, you must
change the oil at 3,000 miles (5 000 km) since the last
oil change. Remember to reset the oil life system
whenever the oil is changed.
5-18

3. Clean the engine air cleaner/filter housing.
4. Inspect or replace the engine air cleaner/filter.
Make sure that the filter fits properly into the
housing.
5. Reinstall the cover and fasten the retaining clips.
{CAUTION:
Operating the engine with the air cleaner/filter
off can cause you or others to be burned. The air
cleaner not only cleans the air; it helps to stop
flames if the engine backfires. If it is not there and
the engine backfires, you could be burned. Do not
drive with it off, and be careful working on the
engine with the air cleaner/filter off.
Notice:If the air cleaner/ lter is off, a back re can
cause a damaging engine re. And, dirt can easily get
into the engine, which will damage it. Always have
the air cleaner/ lter in place when you are driving.
Automatic Transmission Fluid
If your vehicle has the DURAMAX Diesel engine, see
the DURAMAX Diesel manual for more information.
When to Check and Change Automatic
Transmission Fluid
A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change the fluid and filter at the intervals listed in
Additional Required Services on page 6-6, and be sure
to use the transmission fluid listed inRecommended
Fluids and Lubricants on page 6-13.
5-21

How to Check Automatic Transmission
Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealer/retailer service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
parts or exhaust system parts, starting a re.
Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if
you check your transmission uid.
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:
•When outside temperatures are above 90°F (32°C).
•At high speed for quite a while.
•In heavy traffic — especially in hot weather.
•While pulling a trailer.
To get the right reading, the fluid should be at normal
operating temperature, which is 180°F to 200°F
(82°C to 93°C).Get the vehicle warmed up by driving about
15 miles (24 km) when outside temperatures are above
50°F (10°C). If it is colder than 50°F (10°C), drive the
vehicle in D (DRIVE) until the engine temperature gage
moves and then remains steady for 10 minutes.
A cold fluid check can be made after the vehicle has
been sitting for eight hours or more with the engine off,
but this is used only as a reference. Let the engine run
at idle for five minutes if outside temperatures are 50°F
(10°C) or more. If it is colder than 50°F (10°C), you may
have to idle the engine longer. Should the fluid level be
low during this cold check, you must check the fluid hot
before adding fluid. Checking the fluid hot will give you a
more accurate reading of the fluid level.
Checking the Fluid Level
Prepare your vehicle as follows:
1. Park your vehicle on a level place. Keep the engine
running.
2. With the parking brake applied, place the shift lever
in P (PARK).
3. With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position
the shift lever in P (PARK).
4. Let the engine run at idle for three minutes or more.
5-22

Then, without shutting off the engine, follow these steps:
The transmission dipstick
is located near the center
of the engine compartment
and will be labeled with
the graphic shown.
SeeEngine Compartment Overview on page 5-14for
more information on location.
1. Flip the handle up and then pull out the dipstick
and wipe it with a clean rag or paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again.3. Check both sides of the dipstick, and read the lower
level. The fluid level must be in the COLD area
for a cold check or in the HOT or cross-hatched
area for a hot check. Be sure to keep the dipstick
pointed down to get an accurate reading.
4. If the fluid level is in the acceptable range, push the
dipstick back in all the way; then flip the handle
down to lock the dipstick in place.
5-23