fuel GMC YUKON DENALI 2008 Owner's Manual

You can run the engine to keep warm, but be careful.
{CAUTION:
Snow can trap exhaust gases under your
vehicle. This can cause deadly CO (carbon
monoxide) gas to get inside. CO could
overcome you and kill you. You cannot see it
or smell it, so you might not know it is in your
vehicle. Clear away snow from around the
base of your vehicle, especially any that is
blocking the exhaust pipe. And check around
again from time to time to be sure snow does
not collect there.
Open a window just a little on the side of the
vehicle that is away from the wind. This will
help keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little
faster than just idle. That is, push the accelerator
slightly. This uses less fuel for the heat that you get and
it keeps the battery charged. You will need a
well-charged battery to restart the vehicle, and possibly
for signaling later on with the headlamps. Let the
heater run for a while.
4-31

Then, shut the engine off and close the window almost all
the way to preserve the heat. Start the engine again and
repeat this only when you feel really uncomfortable from
the cold. But do it as little as possible. Preserve the fuel
as long as you can. To help keep warm, you can get out
of the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.
If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
Slowly and cautiously spin the wheels to free your
vehicle when stuck in sand, mud, ice, or snow. See
Rocking Your Vehicle to Get It Out on page 4-32.
If your vehicle has a traction system, it can often help to
free a stuck vehicle. Refer to your vehicle’s traction
system in the Index. If the stuck condition is too severe
for the traction system to free the vehicle, turn the
traction system off and use the rocking method.
{CAUTION:
If you let your vehicle’s tires spin at high
speed, they can explode, and you or others
could be injured. The vehicle can overheat,
causing an engine compartment re or other
damage. Spin the wheels as little as possible
and avoid going above 35 mph (55 km/h) as
shown on the speedometer.
For information about using tire chains on your vehicle,
seeTire Chains on page 5-76.
Rocking Your Vehicle to Get It Out
First, turn the steering wheel left and right to clear
the area around the front wheels. For vehicles with
StabiliTrak
®, turn the traction control part of the system
off. SeeStabiliTrak®System on page 4-6. Then shift
back and forth between REVERSE (R) and a forward
gear, spinning the wheels as little as possible.
4-32

This is called Gross Vehicle Weight Rating
(GVWR). The GVWR includes the weight of the
vehicle, all occupants, fuel and cargo.
The Certication/Tire label also tells you the
maximum weights for the front and rear axles,
called Gross Axle Weight Rating (GAWR). To nd
out the actual loads on your front and rear
axles, you need to go to a weigh station and
weigh your vehicle. Your dealer can help you with
this. Be sure to spread out your load equally on
both sides of the centerline.
Never exceed the GVWR for your vehicle, or the
GAWR for either the front or rear axle.
And, if you do have a heavy load, you should
spread it out.
{CAUTION:
Do not load your vehicle any heavier than
the Gross Vehicle Weight Rating (GVWR),
or either the maximum front or rear Gross
Axle Weight Rating (GAWR). If you do,
parts on your vehicle can break, and it
can change the way your vehicle handles.
These could cause you to lose control
and crash. Also, overloading can shorten
the life of your vehicle.
Your warranty does not cover parts or components
that fail because of overloading.
The label will help you decide how much cargo
and installed equipment your truck can carry.
Using heavier suspension components to
get added durability might not change your weight
ratings. Ask your dealer to help you load your
vehicle the right way.
4-38

Towing a Trailer
Do not tow a trailer during break-in. SeeNew Vehicle
Break-In on page 2-25for more information.
{CAUTION:
If you do not use the correct equipment and
drive properly, you can lose control when you
pull a trailer. For example, if the trailer is too
heavy, the brakes may not work well — or even
at all. You and your passengers could be
seriously injured. Pull a trailer only if you have
followed all the steps in this section. Ask your
dealer for advice and information about towing
a trailer with your vehicle.Notice:Pulling a trailer improperly can damage
your vehicle and result in costly repairs not covered
by your warranty. To pull a trailer correctly, follow
the advice in this part, and see your dealer for
important information about towing a trailer with
your vehicle.
To identify the trailering capacity for your vehicle, you
should read the information in “Weight of the Trailer” that
appears later in this section.
Trailering is different than just driving your vehicle by
itself. Trailering means changes in acceleration, braking,
handling, durability and fuel economy. Successful,
safe trailering takes correct equipment, and it has to be
used properly.
That’s the reason for this part. In it are many time-tested,
important trailering tips and safety rules. Many of
these are important for your safety and that of your
passengers. So please read this section carefully before
you pull a trailer.
4-42

Press this button at the end of the shift lever to enable
tow/haul mode.
When the button is pressed, a light on the instrument
panel will illuminate to indicate that Tow/Haul has been
selected. Tow/Haul may be turned off by pressing
the button again, at which time the indicator light on the
instrument panel will turn off. The vehicle will
automatically turn off tow/haul every time it is started.Tow/Haul is designed to be most effective when the
vehicle and trailer combined weight is at least 75 percent
of the vehicle’s Gross Combination Weight Rating
(GCWR). See “Weight of the Trailer” later in this section.
Tow/Haul is most useful under the following driving
conditions:
When pulling a heavy trailer or a large or heavy
load through rolling terrain.
When pulling a heavy trailer or a large or heavy
load in stop and go traffic.
When pulling a heavy trailer or a large or heavy
load in busy parking lots where improved low
speed control of the vehicle is desired.
Operating the vehicle in Tow/Haul when lightly loaded
or with no trailer at all will not cause damage. However,
there is no benet to the selection of Tow/Haul when
the vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a heavy
trailer or a large or heavy load.
4-44

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-3
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside
of Your Vehicle...........................................5-4
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-6
Filling the Tank..............................................5-7
Filling a Portable Fuel Container.......................5-9
Checking Things Under the Hood....................5-10
Hood Release..............................................5-10
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-13
Engine Oil Life System..................................5-16
Engine Air Cleaner/Filter................................5-17
Automatic Transmission Fluid.........................5-20
Engine Coolant.............................................5-23
Coolant Surge Tank Pressure Cap..................5-26
Engine Overheating.......................................5-26
Overheated Engine Protection
Operating Mode........................................5-28Cooling System............................................5-29
Engine Fan Noise.........................................5-34
Power Steering Fluid.....................................5-34
Windshield Washer Fluid................................5-35
Brakes........................................................5-36
Battery........................................................5-39
Jump Starting...............................................5-40
All-Wheel Drive..............................................5-45
Rear Axle.......................................................5-46
Front Axle......................................................5-47
Headlamp Aiming...........................................5-48
Bulb Replacement..........................................5-50
Halogen Bulbs..............................................5-50
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps.........................................5-51
License Plate Lamp......................................5-52
Replacement Bulbs.......................................5-52
Windshield Wiper Blade Replacement..............5-53
Tires..............................................................5-55
Tire Sidewall Labeling...................................5-56
Tire Terminology and Denitions.....................5-58
Ination - Tire Pressure.................................5-60
High-Speed Operation...................................5-62
Tire Pressure Monitor System.........................5-62
Tire Pressure Monitor Operation.....................5-64
Section 5 Service and Appearance Care
5-1

California Perchlorate Materials
Requirements
Certain types of automotive applications, such as airbag
initiators, seat belt pretensioners, and lithium batteries
contained in remote keyless entry transmitters, may
contain perchlorate materials. Special handling may be
necessary. For additional information, see
www.dtsc.ca.gov/hazardouswaste/perchlorate.
Doing Your Own Service Work
{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.If you want to do some of your own service work, you
should 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, see
Service Publications Ordering Information on page 7-14.
Your vehicle has an airbag system. Before attempting
to do your own service work, seeServicing Your
Airbag-Equipped Vehicle on page 1-90.
You should keep a record with all parts receipts and list
the mileage and the date of any service work you
perform. SeeMaintenance Record on page 6-16.
Adding Equipment to the Outside
of Your Vehicle
Things you might add to the outside of your vehicle can
affect the airow 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 your vehicle.
5-4

Fuel
Use of the recommended fuel is an important part of the
proper maintenance of your vehicle. To help keep the
engine clean and maintain optimum vehicle
performance, we recommend the use of gasoline
advertised as TOP TIER Detergent Gasoline.
Gasoline Octane
Use premium unleaded gasoline with a posted octane
rating of 91 or higher. You can also use regular
unleaded gasoline rated at 87 octane or higher, but
your vehicle’s acceleration could be slightly reduced,
and you might notice a slight audible knocking noise,
commonly referred to as spark knock. If the octane is less
than 87, you might notice a heavy knocking noise when
you drive. If this occurs, use a gasoline rated at 87 octane
or higher as soon as possible. Otherwise, you could
damage the engine. If you are using gasoline rated at 87
octane or higher and you hear heavy knocking, the
engine needs service.
Gasoline Specications
At a minimum, gasoline should meet ASTM specication
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 5-6for
additional information.
California Fuel
If your vehicle is certied to meet California Emissions
Standards, it is designed to operate on fuels that meet
California specications. See the underhood emission
control label. If this fuel is not available in states adopting
California emissions standards, your vehicle will operate
satisfactorily on fuels meeting federal specications, but
emission control system performance might be affected.
The malfunction indicator lamp could turn on and your
vehicle might fail a smog-check test. SeeMalfunction
Indicator Lamp on page 3-42. 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 your warranty.
5-5

Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that help prevent
engine and fuel system deposits from forming, allowing
the emission control system to work properly. In most
cases, you should not have to add anything to the fuel.
However, some gasolines contain only the minimum
amount of additive required to meet U.S. Environmental
Protection Agency regulations. To help keep fuel injectors
and intake valves clean, or if your vehicle experiences
problems due to dirty injectors or valves, look for gasoline
that is advertised as TOP TIER Detergent Gasoline. Also,
your dealer/retailer has additives that will help correct and
prevent most deposit-related problems.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines might be available
in your area. We recommend that you use these
gasolines, if they comply with the specications described
earlier. However, E85 (85% ethanol) and other fuels
containing more than 10% ethanol must not be used in
vehicles that were not designed for those fuels.
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in the fuel
system and also damage plastic and rubber parts.
That damage would not be covered under your
warranty.Some gasolines that are not reformulated for low
emissions can contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. We recommend against
the use of such gasolines. Fuels containing MMT can
reduce the life of spark plugs and the performance of the
emission control system could be affected. The
malfunction indicator lamp might turn on. If this occurs,
return to your dealer/retailer for service.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel might be hard
to nd. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel would not be
covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you will be driving.
5-6

Filling the Tank
{CAUTION:
Fuel vapor burns violently and a fuel re can
cause bad injuries. To help avoid injuries to
you and others, read and follow all the
instructions on the pump island. Turn off your
engine when you are refueling. Do not smoke
if you are near fuel or refueling your vehicle.
Do not use cellular phones. Keep sparks,
ames, and smoking materials away from fuel.
Do not leave the fuel pump unattended when
refueling your vehicle. This is against the law in
some places. Do not re-enter the vehicle while
pumping fuel. Keep children away from the fuel
pump; never let children pump fuel.The tethered fuel cap is located behind a hinged fuel
door on the driver’s side of the vehicle.
5-7