Engine Coolant Heater
The engine coolant heater can provide easier starting
and better fuel economy during engine warm-up in cold
weather conditions at or below 0°F (−18°C). Vehicles
with an engine coolant heater should be plugged
in at least four hours before starting the vehicle. An
internal thermostat in the plug-end of the cord may exist
which will prevent engine coolant heater operation at
temperatures above 0°F (−18°C).
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical cord.
The cord is located on the driver side of the
engine compartment next to the battery box facing
the engine.
3. Plug it into a normal, grounded 110-Volt AC outlet.
{CAUTION:
Plugging the cord into an ungrounded outlet could
cause an electrical shock. Also, the wrong kind of
extension cord could overheat and cause a re.
You could be seriously injured. Plug the cord into
a properly grounded three-prong 110-volt AC
outlet. If the cord will not reach, use a heavy-duty
three-prong extension cord rated for at least
15 amps.
4. Before starting the engine, be sure to unplug and
store the cord as it was before to keep it away
from moving engine parts and prevent damage.
The length of time the heater should remain plugged in
depends on several factors. Ask a dealer/retailer in
the area where you will be parking the vehicle for the
best advice on this.
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Rear Window Defogger
The rear window defogger uses a warming grid to
remove fog from the rear window.
<(Rear):Press to turn the rear window defogger on
or off.
An indicator light comes on to show that the rear
window defogger is on.
The rear window defogger will turn off approximately
10 minutes after the button is pressed. If additional
warming time is needed, press the button again.
The heated mirrors will also come on when the rear
window defogger is turned on. SeeOutside Heated
Mirrors on page 2-44.
Notice:Do not use a razor blade or sharp object to
clear the inside rear window. Do not adhere anything
to the defogger grid lines in the rear glass. These
actions may damage the rear defogger. Repairs
would not be covered by your warranty.
Outlet Adjustment
Use the air outlets located in the center and on the side
of the instrument panel to direct the air ow. Use the
thumbwheels near the air outlets to open or close off
the air ow.
Operation Tips
Clear away any ice, snow, or leaves from air inlets
at the base of the windshield that could block the
ow of air into the vehicle.
Keep the path under the front seats clear of objects
to help circulate the air inside of the vehicle more
effectively.
Use of non-GM approved hood de ectors can
adversely affect the performance of the system.
Check with your dealer/retailer before adding
equipment to the outside of the vehicle.
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Gasoline Octane
If the vehicle has the 4.2L L6 engine (VIN Code S) or
the 5.3L V8 engine (VIN Code M), use regular unleaded
gasoline with a posted octane rating of 87 or higher. If the
octane rating is less than 87, you might 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, the engine needs service.
If the vehicle has the 6.0L V8 engine (VIN Code H),
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 the 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 Speci cations
At a minimum, gasoline should meet ASTM speci cation
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 5-7
for additional information.
California Fuel
If the 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, the vehicle will operate
satisfactorily on fuels meeting federal speci cations, but
emission control system performance might be affected.
The malfunction indicator lamp could turn on and the
vehicle might fail a smog-check test. SeeMalfunction
Indicator Lamp on page 3-39. 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 the vehicle warranty.
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