spark plugs GMC ENVOY DENALI 2008 Owners Manual

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.
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Additional Required Services
The following services should be performed at the rst maintenance service (IorII) after the indicated miles (kilometers)
shown for each item.
Additional Required Services
Service and Miles (Kilometers)25,000
(40 000)50,000
(80 000)75,000
(120 000)100,000
(160 000)125,000
(200 000)150,000
(240 000)
Inspect fuel system for damage
or leaks.• •••••
Inspect exhaust system for loose or
damaged components.• •••••
Replace engine air cleaner lter. See
Engine Air Cleaner/Filter on page 5-21.•••
Change automatic transmission uid
and lter (severe service).
See footnotes (g) and (h).•••
Change automatic transmission
uid and lter (normal service).
See footnote (g).•
Automatic transfer case only: Change
transfer case uid.See footnote (g).•••
Replace spark plugs.An Emission
Control Service.•
V8 engine only: Inspect spark plug
wires.An Emission Control Service.•
6-6

Maintenance Replacement Parts
Replacement parts identied below by name, part number, or specication can be obtained from your dealer/retailer.
Part GM Part Number ACDelco®Part Number
Automatic Transmission Filter Kit 24208576 TF337
Engine Air Cleaner/Filter 15036141 A2014C
Engine Oil Filter
4.2L L6 Engine 89017342 PF61
5.3L V8 Engine 89017524 PF48
Spark Plugs
4.2L L6 Engine 12598004 41-103
5.3L V8 Engine 12571164 41-985
Wiper Blades
Front – 22 inches (56 cm) 15214346 —
Rear – 16 inches (41 cm) 15160740 —
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