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{WARNING:
Fuel can spray out on you if you open the fuel cap
too quickly. If you spill fuel and then something
ignites it, you could be badly burned. This spray
can happen if the tank is nearly full, and is more
likely in hot weather. Open the fuel cap slowly and
wait for any hiss noise to stop. Then unscrew the
cap all the way.
Be careful not to spill fuel. Do not top off or overfill the
tank and wait a few seconds after you have finished
pumping before removing the nozzle. Clean fuel from
painted surfaces as soon as possible. SeeWashing
Your Vehicle on page 6-105.
When replacing the fuel cap, turn it clockwise until it
clicks. Make sure the cap is fully installed. The diagnostic
system can determine if the fuel cap has been left off or
improperly installed. This would allow fuel to evaporate
into the atmosphere. SeeMalfunction Indicator Lamp on
page 4-30.
{WARNING:
If a fire starts while you are refueling, do not
remove the nozzle. Shut off the flow of fuel by
shutting off the pump or by notifying the station
attendant. Leave the area immediately.
Notice:If you need a new fuel cap, be sure to get
the right type. Your dealer/retailer can get one
for you. If you get the wrong type, it may not t
properly. This may cause the malfunction indicator
lamp to light and may damage the fuel tank and
emissions system. SeeMalfunction Indicator Lamp
on page 4-30.
6-11
Page 282 of 440

Filling a Portable Fuel Container
{WARNING:
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
{WARNING:
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).
6-12
Page 288 of 440

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 that is needed 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 indicates 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 is indicated can vary considerably.
For the oil life system to work properly, the system
must be reset every time the oil is changed.When the system has calculated that oil life has been
diminished, it indicates that an oil change is necessary.
A CHANGE ENGINE OIL SOON message comes on.
SeeDIC Warnings and Messages on page 4-44. Change
the oil as soon as possible within the next 1 000 km
(600 miles). It is possible that, if 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, the oil must be
changed at 5 000 km (3,000 miles) since the last oil
change. Remember to reset the oil life system whenever
the oil is changed.
6-18
Page 289 of 440

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 the oil is changed 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 the vehicle
is started, 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.
6-19
Page 291 of 440

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.
{WARNING:
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
(4-Speed Transmission)
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
Scheduled Maintenance on page 7-3, and be sure to
use the transmission fluid listed inRecommended Fluids
and Lubricants on page 7-12.
6-21
Page 298 of 440
Cooling System
If your vehicle has a diesel engine, see “Van Models”
under “Cooling System” in the DURAMAX®Diesel
Supplement.
The Cooling System allows the engine to maintain the
correct working temperature.
A. Radiator Pressure Cap
B. Coolant Recovery Tank
C. Engine Cooling Fan(s)
{WARNING:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.
{WARNING:
Heater, fuel operated heater (FOH), radiator
hoses, and other engine parts, can be very hot.
Do not touch them. If you do, you can be burned.
WARNING: (Continued)
6-28
Page 299 of 440
WARNING: (Continued)
Do not run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
Notice:Using coolant other than DEX-COOL may
cause premature engine, heater core, radiator and
fuel operated heater (FOH) corrosion. In addition, the
engine coolant may require changing sooner, at
30,000 miles (50 000 km) or 24 months, whichever
occurs rst. Any repairs would not be covered by
your warranty. Always use DEX-COOL (silicate-free)
coolant in your vehicle.
Engine Coolant
The cooling system in the vehicle is filled with
DEX-COOL®engine coolant. This coolant is designed
to remain in the vehicle for five years or 150,000 miles
(240 000 km), whichever occurs first.
The following explains the cooling system and how to
check and add coolant when it is low. If there is a problem
with engine overheating, seeEngine Overheating on
page 6-35.
6-29
Page 300 of 440

What to Use
{WARNING:
Adding only plain water to the cooling system can
be dangerous. Plain water, or some other liquid
such as alcohol, can boil before the proper coolant
mixture will. The vehicle’s coolant warning system
is set for the proper coolant mixture. With plain
water or the wrong mixture, the engine could get
too hot but you would not get the overheat
warning. The engine could catch fire and you or
others could be burned. Use a 50/50 mixture of
clean, drinkable water and DEX-COOL
®coolant.
Use a 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant. If using this mixture, nothing else
needs to be added. This mixture:
•Gives freezing protection down to−34°F (−37°C),
outside temperature.
•Gives boiling protection up to 265°F (129°C),
engine temperature.
•Protects against rust and corrosion.
•Will not damage aluminum parts.
•Helps keep the proper engine temperature.
Notice:If an improper coolant mixture is used,
the engine could overheat and be badly damaged.
The repair cost would not be covered by the vehicle
warranty. Too much water in the mixture can freeze
and crack the engine, radiator, heater core, and
other parts.
Notice:If extra inhibitors and/or additives are used
in the vehicle’s cooling system, the vehicle could
be damaged. Use only the proper mixture of
the engine coolant listed in this manual for the
cooling system. SeeRecommended Fluids and
Lubricants on page 7-12for more information.
6-30