Of course, traction is reduced when water, snow, ice,
gravel, or other material is on the road. For safety, you
will want to slow down and adjust your driving to
these conditions. It is important to slow down on slippery
surfaces because stopping distance will be longer and
vehicle control more limited.
While driving on a surface with reduced traction, try
your best to avoid sudden steering, acceleration, or
braking, including reducing vehicle speed by shifting to
a lower gear. Any sudden changes could cause the tires
to slide. You may not realize the surface is slippery until
your vehicle is skidding. Learn to recognize warning
clues — such as enough water, ice, or packed snow on
the road to make a mirrored surface — and slow down
when you have any doubt.
Remember: Any Anti-Lock Brake System (ABS) helps
avoid only the braking skid.
Racing or Other Competitive Driving
See your warranty book before using your vehicle for
racing or other competitive driving.
Notice:If you use your vehicle for racing or other
competitive driving, the engine may use more oil than
it would with normal use. Low oil levels can damage
the engine. For information on how to add oil, see
Engine Oil on page 5-16.Z06 Only: Be sure to check the oil level often during
racing or other competitive driving and keep the
level at or near the upper mark that shows the
proper operating range on the engine oil dipstick.
Except Z06: Be sure to check the oil level often
during racing or other competitive driving and keep
the level at or near 1 quart (1 L) above the upper
mark that shows the proper operating range on the
engine oil dipstick. After the competitive driving,
remove excess oil so that the level on the dipstick is
not above the upper mark that shows the proper
operating range.
Vehicles with the Z51 performance package have
greaseable outer ends on both of the rear toe-links.
Under normal use, lubrication should be performed as
described in the maintenance schedule. SeeScheduled
Maintenance on page 6-4andRecommended Fluids
and Lubricants on page 6-12. If you use the vehicle for
racing, lubrication should be performed at the end of
each racing day. See your dealer for lubrication
and make sure any needed repairs are made at once.
Proper procedures for performing these services can be
found in the service manual. SeeService Publications
Ordering Information on page 7-14.
4-18
Gasoline Octane
If your vehicle has the 6.0L V8 engine (VIN Code U), 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.
If your vehicle has the 7.0L V8 engine (VIN Code E),
use premium unleaded gasoline with a posted octane
rating of 91 or higher. For best performance, use
premium unleaded gasoline with a posted octane rating
of 93. In an emergency, you can use regular unleaded
gasoline with an octane rating of 87 or higher. If
87 octane fuel is used, do not perform any aggressive
driving maneuvers such as wide open throttle
applications. You may also hear audible spark knock
during acceleration. Re ll your tank with premium fuel as
soon as possible to avoid damaging your engine. If you
are using gasoline rated at 91 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 3-42. 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.
5-5