2003 GMC SIERRA DENALI engine overheat

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’s side of the engine
compartment, near the power steering fluid
reservoir. If you have a diesel engine, refer to
diesel supplement for location.
3. Plug it into a normal, grounded 11 0-volt AC outlet.
Plugging the cord into an ungrounded outlet
could cause an electrical shock. Also, the
wrong kind of extension cord could overheat
and cause a fire. You could
be seriously
injured. Plug the cord into a properly grounded
three-prong
11 0-volt AC outlet. If the cord
won’t reach, use a heavy-duty three-prong
extension cord rated for at least
15 amps.
4. Before starting the engine, be sure to unplug ana
store the cord as it was before to keep it away
from moving engine parts.
If you don’t, it could be
damaged.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature, the
kind of oil you have, and some other things. Instead
of trying to list everything here, we ask that you contact
your dealer in the area where you’ll be parking your
vehicle. The dealer can give you the best advice for that
particular area.
Automatic Transmission Operation
Your vehicle is equipped with an automatic transmission
that features an electronic shift position indicator
located within the instrument panel cluster. This display
is powered anytime the shift lever
is capable of being
moved out
of PARK (P). See Fuses and Circuit Breakers
on page
5-95.
There are several different positions for your shift lever.
PARK
(P): This position locks your wheels. It’s the
best position to use when you start your engine because
your vehicle can’t move easily.
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DRIVE (D) can be used when towing a trailer, carrying a
heavy load, driving on steep hills or for off-road
driving. You may want to shift the transmission to
THIRD
(3) or, if necessary, a lower gear selection if the
transmission shifts too often.
THIRD
(3): This position is also used for normal driving,
however it offers more power and lower fuel economy
than DRIVE (D).
SECOND
(2): This position gives you more power but
lower fuel economy. You can use SECOND
(2) on
hills. It can help control your speed as you go down
steep mountain roads, but then you would also want to
use your brakes occasionally.
If you manually select SECOND
(2), the transmission
will drive in second gear. You may use this feature
for reducing the speed of the rear wheels when you are
trying to start your vehicle from a stop on slippery
road surfaces. FIRST
(1): This position
gives you even more power
(but lower fuel economy) than SECOND
(2). You
can use it on very steep hills, or in deep snow or mud.
If the shift lever is put in FIRST (1) while the vehicle
is moving forward, the transmission won’t shift into first
gear until the vehicle is going slowly enough.
Notice: If your rear wheels won’t turn, don’t try to
drive. This might happen
if you were stuck in
very deep sand or mud or were up against a solid
object. You could damage your transmission.
Also, if you stop when going uphill, don’t hold your
vehicle there with only the accelerator pedal.
This could overheat and damage the transmission.
Use your brakes or shift into PARK (P) to hold
your vehicle in position on a hill.
On cold days, approximately
32°F (OOC) or colder, your
transmission is designed to shift differently until the
engine reaches normal operating temperature. This is
intended to improve heater performance.
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Move the lever up as far as it will go.
3. Turn the ignition key to LOCK.
4. Remove the key and take it with you. If you can
leave your vehicle with the ignition key in your
hand, your vehicle is
in PARK (P).
Leaving Your Vehicle With the Engine
Running
It can be dangerous to leave your vehicle with
the engine running. Your vehicle could move
suddenly if the shift lever is not fully
in
PARK (P) with the parking brake firmly set.
And, if you leave the vehicle with the engine
running,
it could overheat and even catch fire.
You or others could be injured. Don’t leave
your vehicle with the engine running.
If you have to leave your vehicle with the engine
running, be sure your vehicle is in PARK
(P) and the
parking brake
is firmly set before you leave it. After you
move the shift lever into PARK
(P), hold the regular
brake pedal down. Then, see
if you can move the shift
lever away from PARK
(P) without first pulling it
toward you.
If you can, it means that the shift lever
wasn’t fully locked into PARK (P).
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Engine Coolant Temperature Gage Transmission Temperature Gage
I I
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
(1 00°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
(1 25°C) mark, it indicates
that the cooling system is working beyond its capacity.
See
Engine Overheating on page 5-27.
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
(1 30°C).
At approximately 265°F (13O"C), the message center
will display
a TRANSMISSION 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
(1 27°C).
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CHANGE ENGINE OIL
This message is displayed when the engine oil needs to
be changed.
When you change the engine oil, be sure to reset the
CHANGE ENGINE
OIL message. See Engine Oil, When
to Change
under Engine Oil on page 5-13.
OIL LIFE RESET
This message will appear on the display for about 10
seconds after resetting the change engine oil message.
LOW COOLANT LEVEL
If the engine coolant level is low, this message will
appear on the DIC. Adding coolant will clear the
message.
ENGINE COOLANT HOT
If the cooling system temperature gets hot, this message
will appear in the DIC. Stop the vehicle and let the
engine idle in PARK (P) to allow the coolant to reach a
safe temperature. This message will clear when the
coolant temperature drops to safe operating
temperature.
ENGINE OVERHEATED
If the engine cooling system reaches unsafe
temperatures for operation, this message will appear in
the DIC and you will hear a chime. Stop and turn
off
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the vehicle as soon as it is safe to do so to avoid
severe damage. This message will clear when the
engine has cooled to a safe operating temperature.
OIL PRESSURE LOW
If low oil pressure levels occur, this message will be
displayed on the DIC and a chime will sound. Stop the
vehicle as soon as safely possible and do not operate
it until the cause of the low oil pressure has been
corrected. Check your oil as soon as possible and have
your vehicle serviced.
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
Engine Overheating on page 5-27 for further
information.
BATTERY NOT CHARGING
if the battery is not charging during operation, this
message will appear on the DIC. Driving with this
problem could drain your battery. Have the electrical
system checked as soon as possible. Pressing the
select button will acknowledge this message and clear it
from the DIC display.

Q: Suppose, after stalling, I try to back down the hill
A: Set the parking brake, put your transmission in
PARK (P) and turn
off the engine. Leave the
vehicle and go get some help. Exit
on the uphill
side and stay clear of the path the vehicle would
take
if it rolled downhill.
and decide
I just can’t
do it. What should I do?
Driving Downhill
When off-roading takes you downhill, you’ll want to
consider a number of things:
How steep is the downhill? Will I be able to maintain
vehicle control?
What’s the surface like? Smooth? Rough? Slippery?
Hard-packed dirt? Gravel?
0 Are there hidden surface obstacles? Ruts? Logs?
What’s at the bottom of the hill? Is there a hidden
Boulders?
creek bank or even a river bottom with large
rocks?
If you decide you can go down a hill safely, then try to
keep your vehicle headed straight down, and use a
low gear. This way, engine drag can help your brakes
and they won’t hate to do all the work. Descend slowly,
keeping your vehicle under control at all times. Heavy
braking when going down a
h can
cause your brakes to overheat and fade. This
could cause
loss of control and a serious
accident. Apply the brakes lightly when
descending a hill and use
a low gear to keep
vehicle speed under control.
Q: Are there some things I should not do when
A: Yes! These are important because if you ignore
driving
down a hill?
0
them you could lose control and have a serious
accident.
When driving downhill, avoid turns that take you
across the incline
of the hill. A hill that’s not too
steep to drive down may be too steep to drive
across. You could roll over
if you don’t drive straight
down.
Never go downhill with the transmission in
NEUTRAL (N).
This is called “free-wheeling.” Your brakes will have
to do all the work and could overheat and fade.
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If You Are Stuck: In Sand, Mud, Ice
or Snow
in order to free your vehicle when it is stuck, you will
need to spin the wheels, but you don’t want to spin your
wheels too fast. The method known as “rocking” can
help you aet out when you’re stuck, but you must
use cauti
.
If you let your tires spin at high speed, they
can explode, and you or others could be
injured.
And, the transmission or other parts of
the vehicle can overheat. That could cause an
CAUTION: (Continued) engine compartment fire or other
damage.
When you’re stuck, spin the wheels as little as
possible. Don’t spin the wheels above
25 mph
(55 km/h) as shown on the speedometer.
Nofice: Spinning your wheels can destroy parts of
your vehicle as well as the tires. If you spin the
wheels too fast while shifting your transmission back and forth, you can destroy your transmission.
For information about using tire chains on your
vehicle, see
Tire Chains on page 5-68.
4-42

Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade.
If you don’t shift
down, you might have to use your brakes
so much that
they would get hot and no longer work well.
You can tow in DRIVE
(5). You may want to shift the
transmission to THIRD
(3) or, if necessary, a lower gear
selection
if the transmission shifts too often (e.g.,
under heavy loads and/or hilly conditions).
You may also want to activate the tow/haul mode
if the
transmission shifts too often. See “Tow/Haul Mode”
earlier in this section.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes.
If you turn your
engine
off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar
to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine
off. If you do get
the overheat warning, see
Engine Overheating on
page
5-27.
Parking on Hills
m
You really should not park your vehicle, with a
trailer attached, on a hill.
If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But
if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK
(P) yet.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P).
5. Release the regular brakes.
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