2001 GMC ENVOY cooling

For
a More
Detailed Look at
What's Under the Hood
See Section 6
Service Station Guide
Oil Viscosity
Engine Oil
See Section 6
Engine Oil Dipstick
See Section 6
Fuel
Use unleaded only.
See Section 6
for octane ratings.
Cooling System
See Section 5
Hood Release
See Section 6
Windshield Washer
Fluid
See Section 6
Spare Tire Pressure
See Section 5 & 6
Battery
See Section 6Tire Pressure
See Section 6
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2-14
Endgate/Liftgate
CAUTION:
It can be dangerous to drive with the rear
window, endgate or liftgate open because carbon
monoxide (CO) gas can come into your vehicle.
You can't see or smell CO. It can cause
unconsciousness and even death.
If you must drive with the rear window, endgate
or liftgate open or if electrical wiring or other
cable connections must pass through the seal
between the body and the rear window, endgate
or liftgate:

Make sure all other windows are shut.

Turn the fan on your heating or cooling
system to its highest speed with the setting
on VENT or OUTSIDE AIR. That will force
outside air into your vehicle. See ªComfort
Controlsº in the Index.

If you have air outlets on or under the
instrument panel, open them all the way.
See ªEngine Exhaustº in the Index.
Endgate Release
To open a manual lock system from the outside,
insert the key into the lock and turn it counterclockwise
to unlock the glass.
To open a power lock system from the outside, insert the
key into the lock button and turn it counterclockwise.
All the doors will then unlock.
If your vehicle is equipped with the keyless entry system,
your vehicle does not have a lock on the endgate. It is
equipped with a pushbutton to release the glass.
You may also use the keyless entry system, or the
power door locks (if equipped).
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3-2
Comfort Controls
With this system, you can control the heating, cooling
and ventilation in your vehicle.
Standard Climate Control System
Fan Knob
The knob on the left side of the heating system control panel
controls the fan speed. To increase airflow, move the knob
clockwise. To decrease airflow, move it counterclockwise.Temperature Knob
The middle knob on the control panel lets you select the
relative temperature of the air flowing into the passenger
area of your vehicle. Move the knob clockwise
toward the red area for warmer air. Move the knob
counterclockwise toward the blue area for cooler air.
Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery.
OFF: This setting turns the system off. Some outside
air will still enter the vehicle whenever the vehicle is
moving forward. If outside air entering the vehicle is
warmer than desired, turn the temperature knob fully
counterclockwise and turn the mode knob to VENT.
MAX A/C: This setting provides maximum cooling
with the least amount of work. MAX A/C recirculates
much of the air inside your vehicle so it cools quickly.
This setting directs most of the air through the
instrument panel vents and a small amount through
the floor vents.
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3-4
Temperature Knob
The middle knob on the control panel lets you select
the desired air temperature in your vehicle. This knob
will allow you to adjust the interior air temperature
independently of the function knob setting. Move the
knob clockwise toward 82 for warmer air. Move the
knob counterclockwise toward 66 for cooler air.
Full Hot: If you turn the temperature knob past
82
F (28
C), the system will go into the ªfull hotº
mode. The system will remain at that maximum heating
setting and the fan will blow at the speed the fan knob is
set to. If the fan is in AUTO, it will run at full speed.
Full Cold: If you turn the temperature knob past
66
F (19
C), the system will go into the ªfull coldº
mode. The system will remain at that maximum cooling
setting and the fan will blow at the speed the fan knob is
set to. If the fan is in AUTO, it will run at full speed.
Choosing either maximum setting will not cause the
system to heat or cool any faster.Mode Knob - Automatic Operation
The right knob on the control panel allows you to
choose the direction of air delivery. When the system is
set for automatic operation, sensors will control the air
delivery mode. Air will come primarily from the floor or
instrument panel outlets, with some air directed to the
windshield to prevent fogging.
When the system is in AUTO mode, the air conditioning
light will turn on, and the recirculation and outside air
lights turn off. With the system in full auto control
(both the fan and mode knobs in AUTO), you still
have the ability to override any function. However,
continually overriding the outside air or the A/C
compressor will limit the ability of the system to cool
the vehicle quickly.
If you push a button for a function which is not
available, the light next to that button will flash three
times to alert you that it's not available.
To find your comfort zone, start with the 74
F (23
C)
setting and allow about 20 minutes for the system to
adjust the temperature if necessary.
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3-6
HEATER: This setting directs most of the
warmed air through the heater floor outlets and some
air through the windshield defroster outlets.
BLEND: This setting divides airflow equally
between the heater floor outlet and the windshield
defroster outlets. The air conditioning compressor may
run to dehumidify the air to prevent window fogging.
DEFROST: This setting directs most air through
the windshield defroster outlets and some through the
heater outlets. The air conditioning compressor may run
to dehumidify the air to prevent window fogging.
OUTSIDE AIR: Press this button to force
the system to use outside air. Press it again to close off
the outside air.
Pressing the OUTSIDE AIR button will cancel the
RECIRCULATION button.
RECIRCULATION: Press this button to
limit the amount of outside air entering your vehicle.
This is helpful when you are trying to limit odors
entering your vehicle. In the AUTO mode, the
system will use recirculation as necessary to cool
the air. Pressing the recirculation button will change
the operation to a manual mode. Press this button
again to turn off the recirculation feature.
RECIRCULATION may be selected with the fan knob
in OFF to limit odors, outside air and dust from entering
your vehicle.
Pressing the RECIRCULATION button will cancel the
OUTSIDE AIR button.
A/C: Press this button to turn the air conditioning
on and off. The system will cool and dehumidify the air
inside the vehicle when the A/C light is on.
Air conditioning will be automatically disabled when
the outside temperature drops below a level at which air
conditioning is ineffective.
Remember that in order for the automatic system to perform
well, it needs A/C to provide cooling performance.
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3-7 Air Conditioning
On hot days, open the windows long enough to let hot
inside air escape. This reduces the time it takes for your
vehicle to cool down. Then keep your windows closed
for the air conditioner to work its best.
For quick cool
-down on very hot days, use MAX A/C
with the temperature knob turned to the left. This setting
should be used to keep odors and/or dust from entering
the vehicle. For normal cooling on hot days, use A/C
with the temperature knob turned to the left.
On vehicles equipped with the Electronic Climate Control
system, this same performance can be achieved as long as
the A/C is on and the outside air button is not active.
On cool but sunny days, use BI
-LEVEL A/C to deliver
warm air to the floor and cooler air to the instrument
panel outlets.
When the air conditioner is on, you may sometimes
notice slight changes in your vehicle's engine speed
and power. This is normal because the system is
designed to cycle the compressor on and off to keep
the desired temperature.
Heating
The heater works best if you keep your windows closed
while using it. On cold days, use HEATER with the
temperature knob turned clockwise. BLEND is useful
in cool weather when you have fog or ice on the
windshield or side windows.
If you use the optional engine coolant heater before
starting your engine, your heating system will produce
warmer air faster to heat the passenger compartment in
cold weather. See ªEngine Coolant Heaterº in the Index.
Defogging and Defrosting
On cool, humid days, use BLEND to keep the
windshield and side windows clear.
Use DEFROST to remove fog or ice from the
windshield quickly in extreme humid or cold conditions.
Turn the temperature knob to the right and move the
fan knob toward high.
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3-9 Ventilation System
For mild outside temperatures when little heating or
cooling is needed, use PANEL or VENT to direct
outside air through your vehicle. Airflow is through the
instrument panel outlets.
Your vehicle's ventilation system supplies outside air to
the inside of your vehicle when it is moving. When the
vehicle is not moving, you can get outside air to flow
through by selecting any mode and any fan speed.
You will find air outlets in the center and on the sides of
your instrument panel.You can direct the airflow side
-to-side by turning the
thumbwheel located in the center of the vent. The vent
can be tilted up and down also. To control the amount
of airflow through the outlets, turn the thumbwheel
below the vent.
Ventilation Tips

Keep the hood and front air inlet free of ice, snow or
any other obstruction (such as leaves). The heater
and defroster will work far better, reducing the
chance of fogging the inside of your windows.

When you enter a vehicle in cold weather, move the
fan knob to high for a few moments before driving
off. This helps clear the intake ducts of snow and
moisture, and reduces the chance of fogging the
inside of your windows.

Keep the air path under the front seats clear of
objects. This helps air to circulate throughout
your vehicle.
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4-28
If the water isn't too deep, then drive through it slowly.
At fast speeds, water splashes on your ignition system
and your vehicle can stall. Stalling can also occur if you
get your tailpipe under water. And, as long as your
tailpipe is under water, you'll never be able to start your
engine. When you go through water, remember that
when your brakes get wet, it may take you longer to stop.
CAUTION:
Driving through rushing water can be dangerous.
Deep water can sweep your vehicle downstream
and you and your passengers could drown.
If it's only shallow water, it can still wash away
the ground from under your tires, and you could
lose traction and roll the vehicle over. Don't drive
through rushing water.
See ªDriving Through Waterº in the Index for more
information on driving through water.
After Off-Road Driving
Remove any brush or debris that has collected on
the underbody, chassis or under the hood.
These accumulations can be a fire hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
steering, suspension, wheels, tires and exhaust system
for damage. Also, check the fuel lines and cooling
system for any leakage.
Your vehicle will require more frequent service due to
off
-road use. Refer to the Maintenance Schedule for
additional information.
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