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Gasoline Octane
For all vehicles except those with the 5.3L V8 engine
(VIN Code C), use regular unleaded gasoline with a
posted octane rating of 87 or higher. If the octane rating is
less than 87, you may notice an audible knocking noise
when you drive, commonly referred to as spark knock.
If this occurs, use a gasoline rated at 87 octane or higher
as soon as possible. If you are using gasoline rated at
87 octane or higher and you hear heavy knocking,
your engine needs service.
If your vehicle has the 5.3L V8 engine (VIN Code C), use
premium unleaded gasoline with a posted octane rating
of 91 or higher. You may also use regular unleaded
gasoline rated at 87 octane or higher, but your vehicle’s
acceleration may be slightly reduced, and you may notice
a slight audible knocking noise, commonly referred to as
spark knock. If the octane is less than 87, you may 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 might damage your engine.
If you are using gasoline rated at 87 octane or higher and
you hear heavy knocking, your engine needs service.
Gasoline Speci cations
At a minimum, gasoline should meet ASTM
speci cation D 4814 in the United States or
CAN/CGSB-3.5 in Canada. Some gasolines may
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl (MMT).
General Motors recommends against the use of
gasolines containing MMT. SeeAdditives on page 5-6
for additional information.
California Fuel
If your vehicle is certi ed to meet California Emissions
Standards, it is designed to operate on fuels that
meet California speci cations. 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 speci cations, but emission control system
performance may be affected. The malfunction indicator
lamp may turn on and your vehicle may fail a
smog-check test. SeeMalfunction Indicator Lamp
on page 3-34. 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.
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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.
In most cases, 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. 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 GM dealer has additives
that will help correct and prevent most deposit-related
problems.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area. General Motors recommends that you use
these gasolines if they comply with the speci cations
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 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
recommends against 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.
Fuel E85 (85% Ethanol)
The 8th digit of your vehicle identi cation number (VIN)
shows the code letter or number that identi es your
engine. You will nd the VIN at the top left of the
instrument panel. SeeVehicle Identi cation Number
(VIN) on page 5-93.
If your vehicle has the 3.5L V6 engine (VIN Code K only),
you may use either regular unleaded gasoline or ethanol
fuel containing up to 85% ethanol (E85); also seeFuel on
page 5-4. In all other engines, including the 3.5L V6 (VIN
Code N), use only regular unleaded gasoline.
Only vehicles that have the 3.5L V6 engine (VIN Code K)
may use 85% ethanol fuel (E85). General Motors
encourages 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.
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Many service stations will not have an 85% ethanol
fuel (E85) pump available. The U. S. Department
of Energy has an alternative fuels website
(http://www.eere.energy.gov/afdc/infrastructure/locator.html)
that can help you nd 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
greaterthan 85%.
At a minimum, E85 should meet ASTM
Speci cation D 5798.
To ensure quick starts in the wintertime, the E85 fuel
must be formulated properly for your climate according
to ASTM speci cation D 5798. If you have trouble
starting on E85, it may be because your E85 fuel is not
properly formulated for your climate. If this happens,
switching to gasoline or adding gasoline to your fuel tank
may improve starting. Your vehicle is designed to
accommodate a mixture of gasoline and E85 fuel. For
good starting and heater efficiency below 32°F (0°C), the
fuel mix in the fuel tank should contain no more than
70% ethanol.
E85 has less energy per gallon than gasoline, so you
will need to re ll your fuel tank more often when
using E85 than when you are using gasoline.Notice:Some additives are not compatible with
E85 fuel and may harm your fuel system. Damage
caused by additives would not be covered by
your new vehicle warranty. Do not use additives
with E85 fuel.
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.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may 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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