cooling GMC SIERRA 2001 Owner's Manual

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*
Cooling System
See Section 5*
Hood Release
See Section 6
Windshield Washer
Fluid
See Section 6
Tire Pressure
See Section 6
Spare Tire Pressure
See Section 5
Battery
See Section 6
Fuel
See Section 6*
*For vehicles equipped with a diesel engine, see the Diesel Engine Supplement

2-90
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.
See ªEngine Overheatingº in the Index.
Transmission Temperature Gage
(If Equipped)
United States Canada
Your vehicle may be equipped with a transmission
temperature gage.
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).

2-102
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 Coolantº and ªEngine Coolant
Temperature Gageº in the Index. See 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
(V8 Gasoline Engines Only)
This message is displayed
when the cooling system
temperature gets too hot and
the engine further enters
the engine coolant
protection mode.
If your vehicle is equipped with the 8.1L engine, this
light may come on because of an electronic throttle
control system fault. See ªEngine Overheatingº in
the Index for further information.

3-6
AUTO: If the knob is in AUTO, the fan speed will vary
as the system maintains the selected temperature.
When both the fan control 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 control of functions 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/blower 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.
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.

3-8
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 or attempting to quickly cool down the interior.
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 and
the air will recirculate non
-stop. Press this button again
to turn off the recirculation feature.RECIRCULATION may be selected with the fan control
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.
When in AUTO, the A/C is automatically engaged
when necessary.
Air conditioning will be automatically disabled when
the outside temperature drops below a level which
air conditioning is ineffective.
Remember that in order for the automatic system to perform
well, it needs A/C to provide cooling performance.

3-12 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 RECIRCULATION button 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
button 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.
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.
Maximum air conditioning performance is obtained by
pressing the A/C button, the RECIRCULATION button
and turning the temperature knob fully counterclockwise
to the blue area. This setting also cools air the fastest.
After the vehicle's interior reaches a comfortable
temperature, press the OUTSIDE AIR button to
place the air conditioning system in the normal mode.
Passenger Compartment Air Filter (If Equipped)
If your vehicle has air conditioning, it 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.

3-14
The defogger will shut itself off after several minutes.
If you need additional warming time, press the button
again. You can turn the defogger off at any time by
pressing the button.
If your vehicle is equipped with heated outside mirrors,
the rear window defogger button will also activate the
heated outside mirrors.
Do not attach a temporary vehicle license, tape or decals
across the defogger grid on the rear window.
NOTICE:
Don't use a razor blade or something else sharp
on the inside of the rear window. If you do, you
could cut or damage the warming grid, and the
repairs wouldn't be covered by your warranty.
Ventilation System
For mild outside temperatures when little heating or
cooling is needed, use VENT 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.

4-31
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.

4-40
If you drive regularly in steep country, or if you're planning
to visit there, here are some tips that can make your trips
safer and more enjoyable. See ªOff
-Road Drivingº in the
Index for information about driving off
-road.

Keep your vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system and
transmission. These parts can work hard on
mountain roads.

Know how to go down hills. The most important
thing to know is this: let your engine do some of the
slowing down. Shift to a lower gear when you go
down a steep or long hill.
CAUTION:
If you don't shift down, your brakes could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a hill.
You could crash. Shift down to let your engine
assist your brakes on a steep downhill slope.
CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have to
do all the work of slowing down. They could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a hill.
You could crash. Always have your engine running
and your vehicle in gear when you go downhill.

Know how to go uphill. You may want to shift down to
a lower gear. The lower gears help cool your engine and
transmission, and you can climb the hill better.

Stay in your own lane when driving on two
-lane
roads in hills or mountains. Don't swing wide or cut
across the center of the road. Drive at speeds that let
you stay in your own lane.

As you go over the top of a hill, be alert. There could be
something in your lane, like a stalled car or an accident.

You may see highway signs on mountains that warn of
special problems. Examples are long grades, passing
or no
-passing zones, a falling rocks area or winding
roads. Be alert to these and take appropriate action.

4-77 When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:

Start your engine;

Shift into a gear; and

Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for
more on this. Things that are especially important
in trailer operation are automatic transmission fluid
(don't overfill), engine oil, axle lubricant, belt, cooling
system and brake system. Each of these is covered in
this manual, and the Index will help you find them
quickly. If you're trailering, it's a good idea to review
these sections before you start your trip.
Check periodically to see that all hitch nuts and
bolts are tight.
Trailer Wiring Harness
Your vehicle is equipped with one of the following
wiring harnesses for towing a trailer or hauling a
slide
-in camper.
Basic Trailer Wiring Package
All regular, extended cab crew cab pickups have a
six
-wire trailer towing harness.
The six-wire harness is located at the rear of the vehicle
and is tied to the vehicle's frame. The harness requires
the installation of a trailer
-wiring harness connector,
which is available through your dealer.