2010 GMC YUKON Owner's Manual

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 for service.
Fuel E85 (85% Ethanol)
Vehicles that have a FlexFuel badge and a yellow fuel
cap can use either unleaded gasoline or ethanol fuel
containing up to 85% eithanol (E85). For all other
vehicles, use only the unleaded gasoline described
underGasoline Octane
on page 6‑7.
We encourage the use of E85 in vehicles that are
designed to use it. The ethanol in E85 is a "renewable"
fuel, meaning it is made from renewable sources such
as corn and other crops. Many service stations will not have an 85% ethanol
fuel (E85) pump available. The U.S. Department
of Energy has an alternative fuels website
(www.afdc.energy.gov/afdc/locator/stations/) that
can help you find E85 fuel. Those stations that do have
E85 should have a label indicating ethanol content.
Do not use the fuel if the ethanol content is greater
than 85%.
At a minimum, E85 should meet ASTM Specification
D 5798. By definition, this means that fuel labeled E85
will have an ethanol content between 70% and 85%.
Filling the fuel tank with fuel mixtures that do not meet
ASTM specifications can affect driveability and could
cause the malfunction indicator lamp to come on.
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To ensure quick starts in the wintertime, the E85 fuel
must be formulated properly for your climate according
to ASTM specification D 5798. If you have trouble
starting on E85, it could be because the E85 fuel is
not properly formulated for your climate. If this happens,
switching to gasoline or adding gasoline to the fuel tank
can improve starting. For good starting and heater
efficiency below 0°C (32°F), the fuel mix in the fuel tank
should contain no more than 70% ethanol. It is best
not to alternate repeatedly between gasoline and E85.
If you do switch fuels, it is recommended that you add
as much fuel as possible—do not add less than
11 L (3 gal) when refueling. You should drive the vehicle
immediately after refueling for at least 11 km (7 mi) to
allow the vehicle to adapt to the change in ethanol
concentration.
E85 has less energy per liter (gallon) than gasoline, so
you will need to refill the fuel tank more often when
using E85 than when you are using gasoline. See
Filling the Tank on page 6‑11. Notice:
Some additives are not compatible with E85
fuel and can harm the vehicle's fuel system. Do not
add anything to E85. Damage caused by additives
would not be covered by the vehicle warranty.
Notice: This 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 the
vehicle warranty.
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 find. 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 the vehicle 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.
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Filling the Tank
{WARNING:
Fuel vapor burns violently and a fuel fire can
cause bad injuries. To help avoid injuries to you
and others, read and follow all the instructions on
the fuel pump island. Turn off the engine when
refueling. Do not smoke near fuel or when
refueling the vehicle. Do not use cellular phones.
Keep sparks, flames, and smoking materials away
from fuel. Do not leave the fuel pump unattended
when refueling the 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 side of the vehicle. If the vehicle has
E85 fuel capability, the fuel cap will be yellow and state
that E85 or gasoline can be used. SeeFuel E85
(85% Ethanol) on page 6‑9.
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To open the fuel door, push the rearward center edge in
and release and it will open.
To remove the fuel cap, turn it slowly counterclockwise.
The fuel cap has a spring in it; if the cap is released too
soon, it will spring back to the right.
While refueling, hang the tethered fuel cap from the
hook on the fuel door.
{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. See Washing
Your Vehicle on page 6‑112.
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When replacing the fuel cap, insert the tether in its hole
before tightening the cap. Turn the fuel cap clockwise
until it clicks. It will require more effort to turn the fuel
cap on the last turn as you tighten it. 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 4‑39.
If the vehicle has a Driver Information Center (DIC), the
TIGHTEN GAS CAP message displays if the fuel cap is
not properly installed.
{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 can get one for you.
If you get the wrong type, it may not fit properly.
This may cause the malfunction indicator lamp to
light and may damage the fuel tank and emissions
system. See Malfunction Indicator Lamp
on
page 4‑39.
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.
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Checking Things Under
the Hood
{WARNING:
An electric fan under the hood can start up and
injure you even when the engine is not running.
Keep hands, clothing, and tools away from any
underhood electric fan.
{WARNING:
Things that burn can get on hot engine 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.
Hood Release
To open the hood:
1. Pull the handle withthis symbol on it. It is
located inside the
vehicle to the lower left
of the steering wheel.
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2. Then go to the front of the vehicle and locatethe secondary hood release, near the center
of the grille. 3. Push the secondary hood release to the right.
4. Lift the hood.
Before closing the hood, be sure all the filler caps
are on properly. Then bring the hood from full
open to within 6 inches (152 mm) from the closed
position, pause, then push the front center of
the hood with a swift, firm motion to fully close
the hood.
6-15

Engine Compartment Overview
If the vehicle is a Two-mode Hybrid, see the Two-mode Hybrid manual for more information.
When you open the hood on the 5.3L engine (6.0L and 6.2L similar), here is what you will see:
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