2001 GMC YUKON XL DENALI cooling

For
a More
Detailed Look at
What's Under the Hood
See Section 6
Service Station Guide
Cooling System
See Section 5
Spare Tire Pressure
See Section 6
Tire Pressure
See Section 6
Fuel
Use unleaded only.
See Section 6
for octane ratings.
Oil Viscosity
Engine Oil
See Section 6
Engine Oil Dipstick
See Section 6
Hood Release
See Section 6
Windshield Washer
Fluid
See Section 6Battery
See Section 6

2-12
Liftgate/Liftgate Glass
CAUTION:
It can be dangerous to drive with the liftgate or
liftgate glass 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 liftgate or liftgate glass
open or if electrical wiring or other cable
connections must pass through the seal between
the body and the liftgate or liftgate glass:

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.
To open from the outside, insert the key into the
lock and turn it counterclockwise to unlock the glass
and liftgate.
The liftgate glass can be opened using the pushbutton on
the liftgate after the doors have been unlocked. This can
be done by using either the power door locks or the
remote keyless entry system.
To open the entire liftgate, lift the handle located in the
center of the door.
To lock from the outside, insert the key into the lock
button and turn clockwise. All doors will lock. You may
also use the remote keyless entry system or the power
door locks to lock the liftgate and liftgate glass.
Theft
Vehicle theft is big business, especially in some cities.
Although your vehicle has a number of theft
-deterrent
features, we know that nothing we put on it can make
it impossible to steal. However, there are ways you
can help.

2-70 Engine Coolant Temperature Gage
United States Canada
This gage shows the engine coolant temperature.
It also provides an indicator of how hard your vehicle is
working. During a majority of the operation, the gage
will read 210
F (100
C) or less. If you are pulling a
load or going up hills, it is normal for the temperature to
fluctuate and approach the 250
F (122
C) mark. If the
gage reaches the 260
F (125
C) mark, it indicates that
the cooling system is working beyond its capacity.
The ªProblems on the Road,º section of this manual
shows what to do. See ªEngine Overheatingº in
the Index.
Transmission Temperature Gage
United States Canada
When your ignition is on, the gage shows the temperature
of the transmission fluid. The normal operating range is
from 100
F (38
C) to about 265
F (130
C).
At approximately 265
F (130
C), the message center
will display a TRANS FLUID HOT message and the
transmission will enter a transmission protection mode.
When the transmission enters the protection mode, you
may notice a change in the transmission shifting
patterns. The transmission will return to normal shifting
patterns when the transmission fluid temperature falls
below 260
F (127
C).
See ªMessage Centerº in the Index for further information.

2-80 Low Coolant
This message is displayed
when the cooling system is
low on coolant.
The engine may overheat. See ªEngine Coolantº in the
Index and have your vehicle serviced as soon as you can.
Check Coolant Temp
This message is displayed
when the cooling system
temperature gets hot.
Check the coolant temperature gage and the coolant
level. See ªEngine Coolant,º ªEngine Coolant
Temperature Gageº and ªEngine Overheatingº in the
Index for further information.
Engine Overheated
This message is displayed
when the cooling system
temperature gets too hot.
This message will be displayed after the air conditioning
system has automatically turned off for the engine
coolant protection mode. See ªEngine Overheatingº in
the Index for further information.
Reduced Engine Power
This message is displayed
when the cooling system
temperature gets too hot
and the engine further
enters the engine coolant
protection mode.
See ªEngine Overheatingº in the Index for
further information.

3-2
Comfort Controls
Electronic Climate Control System
Fan Knob
The knob on the left side of the electronic climate
control panel regulates the fan speed. To manually
increase airflow, move the knob clockwise. To manually
decrease airflow, move it counterclockwise.
OFF: If the knob is in OFF, outside air will still enter
the vehicle, and will be directed based on the position
of the mode knob.
AUTO: If the knob is in AUTO, the fan speed will vary
as the system maintains the selected temperature.When both the fan knob and mode knobs are in the
AUTO position, the system will then automatically
maintain the desired cabin temperature as selected
by the temperature knob. Manual operation is
also available.
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
independent of the function knob setting. Move the
knob clockwise toward 82 for warmer air. Move the
knob counterclockwise toward 66 for cooler air. When
the system is set for automatic operation, sensors will
control the fan speed.
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.

3-8 Air Conditioning
On hot days, open the windows long enough to let hot
air inside 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.
The A/C button, below the mode knob, allows the
air coming into your vehicle to be cooled. This setting
is useful for normal cooling on hot days. When you
use A/C with the recirculation button pushed in,
turn off recirculation as soon as the vehicle reaches a
comfortable interior temperature.
Using A/C with the recirculation setting active
allows the air inside your vehicle to be recirculated.
This setting helps to maximize your air conditioner's
performance and your vehicle's fuel economy.
This setting also cools air the fastest and can be used
to keep unwanted odors and/or dust from entering the
vehicle. When using the air conditioner, turn off the
recirculation setting and use the outside air setting after
the vehicle reaches a comfortable interior temperature.
When the right knob on the control panel is between
heater and defrost, the recirculation feature will not
function to reduce window fogging.Passenger Compartment Air Filter
Your vehicle is equipped with a passenger compartment
air filter, which filters outside air entering the vehicle.
For information on replacing the filter see ªPassenger
Compartment Air Filterº in the Index.
Heating
The heater works best if you keep your windows closed
while using it. On cold days, use the heater or vent/heat
setting with the temperature knob in the red area.
On cold days, approximately 32
F (
-0
C) or
lower, you may experience differences in how
the transmission shifts until the engine is warm.
This feature automatically reduces the time it takes for
the engine to reach normal operating temperature and
shortens the time it takes the heater to reach full output.
If you use the engine coolant heater before starting
your engine in cold weather, 20
F (
-8
C) or lower,
the heating system will produce warmer air faster to heat
the passenger compartment.
The use of an engine coolant heater also reduces the
time it takes for the engine to reach normal operating
temperature. For more information, see ªEngine Coolant
Heaterº in the Index.

3-10 Ventilation System
For mild outside temperatures when little heating or
cooling is needed, use outside air to direct outside air
through your vehicle. Air will flow through the
instrument panel outlets.
Your vehicle's ventilation system supplies outside air
to the inside of your vehicle when it is moving. With
the side windows closed, air will flow into the front air
inlet grilles, through the vehicle, and out the air
exhaust valves.
Outside air will also enter the vehicle when the heater or
the air conditioning fan is running, unless you have the
recirculation button pushed in. For more information on
the recirculation button, see ªAir Conditioningº earlier
in this section.
Your vehicle has air outlets
in the center and on the
sides of the instrument
panel and also may be
equipped on the headliner.
You can move the outlets from side
-to-side or up
and down to direct the flow of air. The left driver and
passenger outlets have shut off knobs. Turn the knob
to the left to shut off air flow or to the right to allow air
flow. When you close an outlet, it will increase the flow
of air coming out of any outlets that are open. The
center outlet does not completely shut off airflow.

4-27
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.
Driving at Night
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to be
impaired
-- by alcohol or drugs, with night vision
problems, or by fatigue.