octane HUMMER H2 2008 Owners Manual

Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel.
SeeGasoline Octane on page 5-5. Poor fuel quality
causes the engine not to run as efficiently as designed.
You might notice this as stalling after start-up, stalling
when you put the vehicle into gear, misring, hesitation
on acceleration, or stumbling on acceleration — these
conditions might go away once the engine is warmed up.
This will be detected by the system and cause the
light to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank of the proper fuel to turn the light off.
If none of the above steps have made the light turn
off, your dealer/retailer can check the vehicle. Your
dealer/retailer has the proper test equipment and
diagnostic tools to x any mechanical or electrical
problems that might have developed.Emissions Inspection and
Maintenance Programs
Some state/provincial and local governments have
or might begin programs to inspect the emission
control equipment on your vehicle. Failure to pass
this inspection could prevent you from getting a
vehicle registration.
Here are some things you need to know to help
your vehicle pass an inspection:
Your vehicle will not pass this inspection if the check
engine light is on or not working properly.
Your vehicle will not pass this inspection if the
OBD (on-board diagnostic) system determines that
critical emission control systems have not been
completely diagnosed by the system. The vehicle
would be considered not ready for inspection. This can
happen if you have recently replaced the battery or
if the battery has run down. The diagnostic system is
designed to evaluate critical emission control systems
during normal driving. This can take several days
of routine driving. If you have done this and your
vehicle still does not pass the inspection for lack of
OBD system readiness, your dealer/retailer can prepare
the vehicle for inspection.
3-44

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.....................5-9
Hood Release..............................................5-10
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-13
Engine Oil Life System..................................5-16
Engine Air Cleaner/Filter................................5-18
Automatic Transmission Fluid.........................5-21
Engine Coolant.............................................5-24
Coolant Surge Tank Pressure Cap..................5-26
Engine Overheating.......................................5-27Overheated Engine Protection
Operating Mode.........................................5-28
Cooling System............................................5-29
Engine Fan Noise.........................................5-33
Power Steering Fluid.....................................5-34
Windshield Washer Fluid................................5-35
Brakes........................................................5-36
Battery........................................................5-39
Jump Starting...............................................5-40
Rear Axle.......................................................5-45
Four-Wheel Drive............................................5-46
Front Axle......................................................5-47
Bulb Replacement..........................................5-48
Halogen Bulbs..............................................5-48
Headlamps..................................................5-48
Front Turn Signal and Parking Lamps..............5-49
Daytime Running Lamps (DRL).......................5-50
Roof Marker Lamps......................................5-50
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps.........................................5-51
Replacement Bulbs.......................................5-53
Windshield Wiper Blade Replacement..............5-54
Tires..............................................................5-55
Tire Sidewall Labeling...................................5-56
Tire Terminology and Denitions.....................5-58
Section 5 Service and Appearance Care
5-1

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

This schedule is for vehicles that:
carry passengers and cargo within recommended
limits. You will nd these limits on the Tire and
Loading Information label. SeeLoading Your
Vehicle on page 4-44.
are driven on reasonable road surfaces within legal
driving limits.
are driven off-road in the recommended manner.
SeeOff-Road Driving on page 4-13.
use the recommended fuel. SeeGasoline Octane
on page 5-5.
The services inScheduled Maintenance on page 6-4
should be performed when indicated. SeeAdditional
Required Services on page 6-6andMaintenance
Footnotes on page 6-7for further information.
{CAUTION:
Performing maintenance work on a vehicle can
be dangerous. In trying to do some jobs, you
can be seriously injured.
CAUTION: (Continued)
CAUTION: (Continued)
Do your own maintenance work only if you
have the required know-how and the proper
tools and equipment for the job. If you have
any doubt, see your dealer/retailer to have a
qualied technician do the work. SeeDoing
Your Own Service Work on page 5-4.
Some maintenance services can be complex. So,
unless you are technically qualied and have the
necessary equipment, you should have your
dealer/retailer do these jobs.
When you go to your dealer/retailer for your service
needs, you will know that trained and supported service
technicians will perform the work using genuine parts.
If you want to purchase service information, seeService
Publications Ordering Information on page 7-15.
Owner Checks and Services on page 6-8tells you what
should be checked, when to check it, and what you
can easily do to help keep your vehicle in good
condition.
6-3

Fuel............................................................... 5-5
Additives...................................................... 5-6
California Fuel.............................................. 5-5
Filling a Portable Fuel Container..................... 5-9
Filling the Tank............................................. 5-7
Fuels in Foreign Countries.............................. 5-6
Gage.........................................................3-47
Gasoline Octane........................................... 5-5
Gasoline Specications.................................. 5-5
Low Warning Light.......................................3-48
Fuses
Center Instrument Panel Fuse Block.............5-112
Fuses and Circuit Breakers.........................5-110
Instrument Panel Fuse Block.......................5-111
Underhood Fuse Block...............................5-113
Windshield Wiper.......................................5-110
G
Gage
Engine Coolant Temperature.........................3-40
Fuel..........................................................3-47
Oil Pressure...............................................3-45
Speedometer..............................................3-33
Tachometer.................................................3-33
Voltmeter Gage...........................................3-37
Garage Door Opener.......................................2-57
Gasoline
Octane........................................................ 5-5
Specications............................................... 5-5Glove Box.....................................................2-64
GM Mobility Reimbursement Program.................. 7-6
H
Hazard Warning Flashers................................... 3-6
Head Restraints............................................... 1-7
Headlamps....................................................5-48
Bulb Replacement.......................................5-48
Daytime Running Lamps.......................3-17, 5-50
Exterior Lamps............................................3-15
Flash-to-Pass............................................... 3-9
Front Turn Signal and Parking Lamps.............5-49
Halogen Bulbs............................................5-48
High/Low Beam Changer................................ 3-8
On Reminder..............................................3-17
Roof Marker Lamps.....................................5-50
Heated Seats................................................... 1-4
Heater...........................................................3-22
Highbeam On Light.........................................3-47
Highway Hypnosis...........................................4-34
Hill and Mountain Roads..................................4-35
Hood
Checking Things Under.................................. 5-9
Release.....................................................5-10
Horn............................................................... 3-6
How to Wear Safety Belts Properly...................1-22
6