HUMMER H3 2010 Owners Manual

Driving and Operating 9-67
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.eere.energy.gov/afdc/
infrastructure/locator.html) 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.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 (three gallons) when
refueling. You should drive the
vehicle immediately after refueling
for at least 11 km (seven miles) to
allow the vehicle to adapt to the
change in ethanol concentration. E85 has less energy per 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 9‑68.
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.

9-68 Driving and Operating
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 fuel cap is located on the driver
side of the vehicle.
To remove the fuel cap, turn it
slowly counterclockwise. While
refueling, let the fuel cap hang by
the tether, if it has one.
When reinstalling the cap, turn
it clockwise until three clicks,
otherwise the Malfunction
Indicator Lamp could turn on.
SeeMalfunction Indicator Lamp
on
page 5‑12.
{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
Exterior Care on page 10‑92.
When replacing the fuel cap,
turn it clockwise until three clicks.
Make sure the cap is fully installed.
The diagnostic system can
determine if the fuel cap has been
left off or improperly installed.

Driving and Operating 9-69
This would allow fuel to evaporate
into the atmosphere. See
Malfunction Indicator Lamp
on
page 5‑12.
The FUEL CAP message displays
on the Driver Information Center
(DIC) if the fuel cap is not properly
installed. See Fuel System
Messages
on page 5‑24for
more information.
{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 a new fuel cap is
needed, be sure to get the right
type of cap from your dealer.
The wrong type fuel cap might
not fit properly, might cause the
malfunction indicator lamp to light, and could damage the fuel
tank and emissions system.
See
Malfunction Indicator Lamp
on page 5‑12.
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.
(Continued)
WARNING (Continued)
.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.

9-70 Driving and Operating
Towing
General Towing
Information
Only use towing equipment that
has been designed for the vehicle.
Contact your dealer or trailering
retailer for assistance with preparing
the vehicle for towing a trailer.
See the following trailer towing
information in this section:
.For information on driving while
towing a trailer, see“Driving
Characteristics and
Towing Tips”.
.For maximum vehicle and trailer
weights, see “Trailer Towing”.
.For information on equipment
to tow a trailer, see “Towing
Equipment”. For information on towing a disabled
vehicle, see
Towing the Vehicle
on
page 10‑90. For information on
towing the vehicle behind another
vehicle —such as a motorhome,
see Recreational Vehicle Towing
on
page 10‑90.
Driving Characteristics
and Towing Tips
{WARNING
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly.
For example, if the trailer is too
heavy, the brakes may not work
well —or even at all. The driver
and passengers could be
seriously injured. The vehicle
may also be damaged; the
resulting repairs would not be
covered by the vehicle warranty.
(Continued)
WARNING (Continued)
Pull a trailer only if all the steps in
this section have been followed.
Ask your dealer for advice and
information about towing a trailer
with the vehicle.
Notice: Pulling a trailer
improperly can damage the
vehicle and result in costly
repairs not covered by the
vehicle warranty. To pull a trailer
correctly, follow the advice in this
section and see your dealer for
important information about
towing a trailer with the vehicle.
The vehicle can tow a trailer when it
is equipped with the proper trailer
towing equipment. For trailering
capacity, see Trailer Towing
on
page 9‑74. Trailering changes
handling, acceleration, braking,
durability and fuel economy.

Driving and Operating 9-71
With the added weight, the engine,
transmission, wheel assemblies and
tires are forced to work harder and
under greater loads. The trailer also
adds wind resistance, increasing
the pulling requirements. For safe
trailering, correctly use the proper
trailering equipment.
The following information has
important trailering tips and rules
for your safety and that of your
passengers. Read this section
carefully before pulling a trailer.
Pulling A Trailer
Here are some important points:
.There are many laws, including
speed limit restrictions that apply
to trailering. Check for legal
requirements with state or
provincial police.
.Consider using a sway control.
See“Hitches” later in this
section.
.Do not tow a trailer at all during
the first 800 km (500 miles) the
new vehicle is driven. The
engine, axle or other parts could
be damaged.
.Then, during the first 800 km
(500 miles) that a trailer is
towed, do not drive over 80 km/h
(50 mph) and do not make starts
at full throttle. This helps the
engine and other parts of the
vehicle wear in at the heavier
loads.
.Vehicles with an automatic
transmission can tow in
D (Drive). Use a lower gear if
the transmission shifts too often.
For vehicles with a manual
transmission, it is better not to
use the highest gear.
.This vehicle has a Hill Start
Assist feature, which may be
useful when the vehicle is
stopped on a grade. See Hill
Start Assist (HSA)
on page 9‑52for more information.
.Do not drive faster than the
maximum posted speed for
trailers.
Driving with a Trailer
Towing a trailer requires experience.
Get familiar with handling and
braking with the added trailer
weight. The vehicle is now longer
and not as responsive as the
vehicle is by itself.
Check all trailer hitch parts and
attachments, safety chains,
electrical connectors, lamps, tires
and mirror adjustments. If the trailer
has electric brakes, start the vehicle
and trailer moving and then apply
the trailer brake controller by hand
to be sure the brakes are working.
During the trip, check occasionally
to be sure that the load is secure,
and the lamps and trailer brakes are
working properly.

9-72 Driving and Operating
Towing with a Stability Control
System
When towing, the sound of the
stability control system might be
heard. The system is reacting to the
vehicle movement caused by the
trailer, which mainly occurs during
cornering. This is normal when
towing heavier trailers.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving the vehicle without a trailer.
This can help to avoid situations
that require heavy braking and
sudden turns.
Passing
More passing distance is needed
when towing a trailer. Because the
rig is longer, it is necessary to go
much farther beyond the passed
vehicle before returning to the lane.
Backing Up
Hold the bottom of the steering
wheel with one hand. Then, to move
the trailer to the left, move that hand
to the left. To move the trailer to the
right, move your hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making Turns
Notice:Making very sharp turns
while trailering could cause the
trailer to come in contact with the
vehicle. The vehicle could be
damaged. Avoid making very
sharp turns while trailering.
When turning with a trailer, make
wider turns than normal. Do this
so the trailer won't strike soft
shoulders, curbs, road signs, trees
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance.
Turn Signals When Towing a
Trailer
The arrows on the instrument panel
flash whenever signaling a turn or
lane change. Properly hooked up,
the trailer lamps also flash, telling
other drivers the vehicle is turning,
changing lanes or stopping.
When towing a trailer, the arrows on
the instrument panel flash for turns
even if the bulbs on the trailer are
burned out. For this reason you
may think other drivers are seeing
the signal when they are not. It is
important to check occasionally to
be sure the trailer bulbs are still
working.
Driving On Grades
Reduce speed and shift to a
lower gear before starting down a
long or steep downgrade. If the
transmission is not shifted down, the
brakes might have to be used so
much that they would get hot and no
longer work well.

Driving and Operating 9-73
Vehicles with an automatic
transmission can tow in D (Drive).
Shift the transmission to a lower
gear if the transmission shifts too
often under heavy loads and/or
hilly conditions. For vehicles with a
manual transmission, it is better not
to use the highest gear.
When towing at high altitude on
steep uphill grades, consider the
following: Engine coolant will boil at
a lower temperature than at normal
altitudes. If the engine is turned off
immediately after towing at high
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
automatic transmission in P (Park)
for a few minutes before turning the
engine off. For vehicles with manualtransmissions, let the engine run
while parked, preferably on level
ground, with the transmission out of
gear and the parking brake applied,
for a few minutes before turning the
engine off. If the overheat warning
comes on, see
Engine Overheating
on page 10‑22.
Parking on Hills
{WARNING
Parking the vehicle on a hill
with the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface. If parking the rig on a hill:
1. Press the brake pedal, but do
not shift into P (Park) yet for
vehicles with an automatic
transmission, or into gear
for vehicles with a manual
transmission. Turn the wheels
into the curb if facing downhill
or into traffic if facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the brake pedal
until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking brake and shift
into P (Park) for vehicles with an
automatic transmission or into
gear for vehicles with a manual
transmission.
5. Release the brake pedal.

9-74 Driving and Operating
Leaving After Parking on a Hill
1. Apply and hold the brake pedalwhile you:
.start the engine,
.shift into a gear, and
.release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See this
manual's Maintenance Schedule
or Index for more information.
Things that are especially important
in trailer operation are automatic
transmission fluid, engine oil, axle lubricant, belts, cooling system and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Engine Cooling When Trailer
Towing
The cooling system may temporarily
overheat during severe operating
conditions. See
Engine Overheating
on page 10‑22.
Trailer Towing
Three important considerations
have to do with weight:
.The weight of the trailer.
.The weight of the trailer tongue.
.The total weight on the vehicle's
tires.
Weight of the Trailer
How heavy can a trailer safely be?
Speed, altitude, road grades,
outside temperature, special
equipment, and the amount of
tongue weight the vehicle can carry
must be considered. See “Weight of
the Trailer Tongue” later in this
section for more information.
Maximum trailer weight is calculated
assuming only the driver is in the
tow vehicle and it has all the
required trailering equipment.
The weight of additional optional
equipment, passengers and cargo in
the tow vehicle must be subtracted
from the maximum trailer weight.
Use the following chart to determine
how much a vehicle can weigh,
based on the vehicle model and
options.

Driving and Operating 9-75
VehicleAxle Ratio Maximum Trailer Weight *GCWR
H3 3.7L L5 Engine, Automatic
Transmission 4.56
4,500 lbs (2 041 kg) 9,500 lbs (4 309 kg)
3.7L L5 Engine, Manual
Transmission 4.56
3,000 lbs (1 361 kg) 8,000 lbs (3 629 kg)
5.3L V8 Engine, Automatic
Transmission 4.10
6,000 lbs (2 721 kg) 11,400 lbs (5 171 kg)
H3T 3.7L L5 Engine, Automatic
Transmission 4.56
4,400 lbs (1 996 kg) 9,500 lbs (4 309 kg)
3.7L L5 Engine, Manual
Transmission 4.56
2,900 lbs (1 315 kg) 8,000 lbs (3 629 kg)
5.3L V8 Engine, Automatic
Transmission 4.10
5,900 lbs (2 676 kg) 11,400 lbs (5 171 kg)
*The Gross Combination Weight Rating (GCWR) in the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for the vehicle should not be
exceeded.

9-76 Driving and Operating
Ask your dealer for our trailering
information or advice, or write us at
our Customer Assistance Offices.
SeeCustomer Assistance Offices
on page 13‑3for more information.
Weight of the Trailer Tongue
The tongue load (A) of any trailer is
an important weight to measure
because it affects the total gross
weight of the vehicle. The Gross
Vehicle Weight (GVW) includes the
curb weight of the vehicle, any
cargo carried in it, and the people
who will be riding in the vehicle.
If there are a lot of options,
equipment, passengers or cargo in
the vehicle, it will reduce the tongue
weight the vehicle can carry, which
will also reduce the trailer weight the
vehicle can tow. If towing a trailer,
the tongue load must be added to
the GVW because the vehicle will
be carrying that weight, too. See
Vehicle Load Limits
on page 9‑27for more information about the
vehicle's maximum load capacity.
If a weight-carrying hitch or a
weight-distributing hitch is being
used, the trailer tongue (A) should
weigh 10‐15 percent of the total
loaded trailer weight (B) up to a
maximum of 227 kg (500 lbs).
After loading the trailer, weigh
the trailer and then the tongue,
separately, to see if the weights are
proper. If they are not, adjustments
might be made by moving some
items around in the trailer. Trailering may be limited by the
vehicle's ability to carry tongue
weight. Tongue weight cannot cause
the vehicle to exceed the GVWR
(Gross Vehicle Weight Rating) or
the RGAWR (Rear Gross Axle
Weight Rating). The effect of
additional weight may reduce the
trailering capacity more than the
total of the additional weight.
Choose the shortest hitch extension
that will position the hitch ball
closest to the vehicle. This will help
reduce the effect of trailer tongue
weight on the rear axle.
If the spare tire carrier is mounted
on the back of the vehicle and the
hitch extension is too short, the
spare tire may interfere with trailer
coupling or trailer tongue jack
operation on some types of trailers.