Page 257 of 404

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
Page 258 of 404
When to Add Engine Oil
If the oil is below the cross-hatched area at the tip
of the dipstick, add at least one quart/liter of the
recommended oil. This section explains what kind
of oil to use. For engine oil crankcase capacity,
seeCapacities and Specifications on page 5-110.
Notice:Do not add too much oil. If the engine
has so much oil that the oil level gets above the
cross-hatched area that shows the proper operating
range, the engine could be damaged.SeeEngine Compartment
Overview on page 5-14
for the location of the
engine oil fill cap.
Add enough oil to put the level somewhere in the proper
operating range. Push the dipstick all the way back in
when you are through.
5-16
Page 259 of 404

What Kind of Engine Oil to Use
Look for three things:
•GM6094M
Use only an oil that meets GM Standard GM6094M.
•SAE 5W-30
SAE 5W-30 is best for the vehicle. These numbers
on an oil container show its viscosity, or thickness.
Do not use other viscosity oils such as SAE 20W-50.
•American Petroleum Institute (API) starburst symbol
Oils meeting these
requirements should have
the starburst symbol on
the container. This symbol
indicates that the oil has
been certified by the
American Petroleum
Institute (API).
Notice:Use only engine oil identi ed as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certi ed For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
the vehicle warranty.
Cold Temperature Operation
If you are in an area of extreme cold, where the
temperature falls below−20°F (−29°C), use either an
SAE 5W-30 synthetic oil or an SAE 0W-30 engine oil.
Both provide easier cold starting for the engine at
extremely low temperatures. Always use an oil that
meets the required specification, GM6094M. See
“What Kind of Engine Oil to Use” for more information.
5-17
Page 260 of 404

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 3-50. 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
Page 261 of 404

How to Reset the Engine Oil Life
System
The Engine Oil Life System calculates when to change
the engine oil and filter based on vehicle use. Whenever
the oil is changed, reset the system so it can calculate
when the next oil change is required. If a situation occurs
where you change the oil prior to a CHANGE ENGINE
OIL SOON message being turned on, reset the system.
To reset the CHANGE ENGINE OIL SOON message:
1. Turn the ignition key to ON/RUN with the engine off.
2. Fully press and release the accelerator pedal
slowly three times within five seconds.
3. Turn the key to LOCK/OFF.
If the message comes back on when you start the
vehicle, the engine oil life system has not reset.
Repeat the procedure. If it still does not reset,
see your dealer/retailer for service.
What to Do with Used Oil
Used engine oil contains certain elements that can be
unhealthy for your skin and could even cause cancer.
Do not let used oil stay on your skin for very long.
Clean your skin and nails with soap and water, or a good
hand cleaner. Wash or properly dispose of clothing or
rags containing used engine oil. See the manufacturer’s
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
filter before disposal. Never dispose of oil by putting it
in the trash, pouring it on the ground, into sewers, or into
streams or bodies of water. Recycle it by taking it to a
place that collects used oil.
5-19
Page 262 of 404
Engine Air Cleaner/Filter
If your vehicle has the DURAMAX Diesel engine, see
the DURAMAX Diesel manual for more information.
The engine air cleaner/filter is located near the center of
the engine compartment. SeeEngine Compartment
Overview on page 5-14for more information on location.
When to Inspect the Engine Air
Cleaner/Filter
Inspect the air cleaner/filter at the MaintenanceII
intervals and replace it at the first oil change after
each 50,000 mile (80 000 km) interval. SeeScheduled
Maintenance on page 6-4for more information.
If you are driving in dusty/dirty conditions, inspect
the filter at each engine oil change.
How to Inspect the Engine Air
Cleaner/Filter
To inspect the air cleaner/filter, remove the filter from
the vehicle and lightly shake the filter to release loose
dust and dirt. If the filter remains caked with dirt, a new
filter is required. Never use compressed air to clean
the filter.
5-20
Page 263 of 404

To inspect or replace the engine air cleaner/filter, do the
following:
1. Unhook the retainer clips and remove the cover.
2. Lift the filter out of the engine air cleaner/filter
housing. Care should be taken to dislodge as
little dirt as possible.
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
Page 264 of 404

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.
5-22