spark plugs HUMMER H2 2004 Owners Manual

California Fuel
If your vehicle is certied to meet California Emission
Standards (see the underhood emission control label), it
is designed to operate on fuels that meet California
specications. 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
may be affected. The malfunction indicator lamp may
turn on (seeMalfunction Indicator Lamp on page 3-38)
and your vehicle may fail a smog-check test. If this
occurs, return to your authorized GM dealer for
diagnosis. If it is determined that the condition is caused
by the type of fuel used, repairs may not be covered
by your warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work
properly. You should not have to add anything to your
fuel. However, some gasolines contain only the
minimum amount of additive required to meet U.S.
Environmental Protection Agency regulations. General
Motors recommends that you buy gasolines that
are advertised to help keep fuel injectors and intakevalves clean. If your vehicle experiences problems due
to dirty injectors or valves, try a different brand of
gasoline.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area to contribute to clean air. General Motors
recommends that you use these gasolines, particularly if
they comply with the specications described earlier.
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage would not be covered under
your warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors does not
recommend the use of such gasolines. Fuels containing
MMT can reduce the life of spark plugs and the
performance of the emission control system may be
affected. The malfunction indicator lamp may turn on. If
this occurs, return to your authorized GM dealer for
service.
5-6

Additional Required Services (cont’d)
Service and Miles (Kilometers)25,000
(41 500)50,000
(83 000)75,000
(125 000)100,000
(166 000)125,000
(207 500)150,000
(240 000)
Change automatic transmission uid
and lter (normal service).•
Change transfer case uid.See
footnote (g).•••
Replace engine air cleaner lter. See
Engine Air Cleaner/Filter on page 5-19.
An Emission Control Service.•
Replace spark plugs and inspect spark
plug wires.An Emission Control
Service.•
Engine cooling system service (or
every 5 years, whichever occurs rst).
An Emission Control Service. See
footnote (i).•
Inspect engine accessory drive belt.An
Emission Control Service.•
6-7

Normal Maintenance Replacement Parts
Replacement parts identied below by name, part number or specication can be obtained from your dealer.
Part ACDelco®Part No. GM Part No.
Engine Oil Filter PF44 25010633
Engine Air Cleaner/Filter — 88944151
Spark Plugs 41–985 12571164
Fuel Filter GF626 25121792
Windsheield Wiper Blades
17.0 inches (43.0 cm)— 15706394
Rear Wiper Blades 11.0 inches (28.0 cm) — 15174476
6-14