2006 GMC SIERRA engine overheat

Driving Downhill
When off-roading takes you downhill, you will want to
consider a number of things:
How steep is the downhill? Will I be able to maintain
vehicle control?
What is the surface like? Smooth? Rough?
Slippery? Hard-packed dirt? Gravel?
Are there hidden surface obstacles? Ruts? Logs?
Boulders?
What is at the bottom of the hill? Is there a hidden
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 the brakes and they
will not have to do all the work. Descend slowly, keeping
your vehicle under control at all times.
{CAUTION:
Heavy braking when going down a hill 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
driving down a hill?
A:Yes! These are important because if you ignore
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 is not too
steep to drive down may be too steep to drive
across. You could roll over if you do not drive
straight down.
Never go downhill with the transmission in
NEUTRAL (N), or with the clutch pedal pressed
down with a manual transmission. This is called
“free-wheeling.” The brakes will have to do all the
work and could overheat and fade.
4-27

If Your Vehicle is 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 do not want to spin your
wheels too fast. The method known as rocking can help
you get out when you are stuck, but you must use
caution.
{CAUTION:
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
engine compartment re or other damage.
When you are stuck, spin the wheels as little
as possible. Do not spin the wheels above
35 mph (55 km/h) as shown on the
speedometer.Notice: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 more information about using tire chains on your
vehicle, seeTire Chains on page 5-89.
Rocking Your Vehicle to Get It Out
First, turn your steering wheel left and right. That
will clear the area around your front wheels. If you have
a four-wheel-drive vehicle, shift into Four-Wheel
High. If your vehicle has the traction assist system, you
should turn it off by pressing the TAS on/off button.
Then shift back and forth between REVERSE (R) and a
forward gear, or with a manual transmission, between
FIRST (1) or SECOND (2) and REVERSE (R), spinning
the wheels as little as possible. Release the accelerator
pedal while you shift, and press lightly on the
accelerator pedal when the transmission is in gear. By
slowly spinning your wheels in the forward and
reverse directions, you will cause a rocking motion that
may free your vehicle. If that does not get you out
after a few tries, you may need to be towed out. Or, you
can use your recovery hooks if your vehicle has
them. If you do need to be towed out, seeTowing Your
Vehicle on page 4-62.
4-46

Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns than
normal. Do this so your trailer won’t strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
The arrows on your instrument panel will ash whenever
you signal a turn or lane change. Properly hooked up, the
trailer lamps will also ash, telling other drivers you’re
about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will ash for turns even if the bulbs on the trailer are
burned out. Thus, you may think drivers behind you are
seeing your signal when they are not. It’s important to
check occasionally to be sure the trailer bulbs are still
working.
Driving On Grades
Reduce speed and shift to a lower gearbeforeyou 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.If you have an automatic transmission, you can tow
in DRIVE (D). You may want to shift the transmission to
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. SeeTow/Haul Mode
Light on page 3-50.
If you have a 5-speed manual transmission and you are
towing a trailer, it’s better not to use FIFTH (5) gear.
Just drive in FOURTH (4) gear (or, as you need to, a
lower gear).
If you have a 6-speed manual transmission and you are
towing a trailer, it’s better not to use SIXTH (6) gear.
Drive in FIFTH (5) gear (or, as you need to, a lower gear).
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant at or near sea level
will boil at a lower temperature than at higher 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
at least ve minutes before turning the engine off. For
manual transmissions, let the engine run while parked,
preferably on level ground, with the transmission out
of gear and the parking brake applied, for at least ve
minutes before turning the engine off. If you do get the
overheat warning, seeEngine Overheating on page 5-37.
4-90

Service............................................................5-4
Accessories and Modications..........................5-4
California Proposition 65 Warning.....................5-4
Doing Your Own Service Work.........................5-5
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-6
Gasoline Specications....................................5-6
California Fuel...............................................5-7
Additives.......................................................5-7
Fuel E85 (85% Ethanol)..................................5-8
Fuels in Foreign Countries...............................5-9
Filling the Tank............................................5-10
Filling a Portable Fuel Container.....................5-11
Checking Things Under the Hood....................5-12
Hood Release..............................................5-13
Engine Compartment Overview.......................5-14
Engine Oil (Gasoline Engine)..........................5-20
Engine Oil Life System (Gasoline Engine)........5-23
Engine Air Cleaner/Filter (Gasoline Engines).......5-25
Automatic Transmission Fluid
(Except Allison Transmission
®) ....................5-28Automatic Transmission Fluid
(Allison Transmission
®) ...............................5-30
Manual Transmission Fluid.............................5-33
Hydraulic Clutch...........................................5-34
Engine Coolant.............................................5-35
Coolant Surge Tank Pressure Cap..................5-37
Engine Overheating.......................................5-37
Overheated Engine Protection Operating Mode
(V8 Engines Only)......................................5-39
Cooling System............................................5-40
Engine Fan Noise.........................................5-45
Power Steering Fluid.....................................5-45
Windshield Washer Fluid................................5-46
Brakes........................................................5-47
Battery........................................................5-51
Jump Starting...............................................5-52
Rear Axle.......................................................5-58
Four-Wheel Drive............................................5-59
Front Axle......................................................5-60
Noise Control System.....................................5-62
Tampering with Noise Control System
Prohibited.................................................5-62
Section 5 Service and Appearance Care
5-1

Automatic Transmission Fluid
(Except Allison Transmission
®)
When to Check and Change Automatic
Transmission Fluid
A good time to check your automatic transmission uid
level is when the engine oil is changed.
Change the uid and lter at the intervals listed in
Additional Required Services (Gasoline Engine) on
page 6-7, and be sure to use the transmission uid
listed inRecommended Fluids and Lubricants
(Gasoline Engine) on page 6-14.
How to Check Automatic
Transmission Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealership service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
Notice:Too much or too little uid can damage
your transmission. Too much can mean that some
of the uid could come out and fall on hot engine
part or exhaust system parts, starting a re.Too little uid could cause the transmission to
overheat. Be sure to get an accurate reading if you
check your transmission uid.
Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
To get the right reading, the uid should be
at normal operating temperature, which is
180°F to 200°F (82°C to 93°C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above
50°F (10°C). If it is colder than 50°F (10°C), drive the
vehicle in THIRD (3) until the engine temperature
gage moves and then remains steady for 10 minutes.
A cold uid check can be made after the vehicle
has been sitting for eight hours or more with the engine
off, but this is used only as a reference. Let the
engine run at idle for ve minutes if outside
temperatures are 50°F (10°C) or more. If it is colder
than 50°F (10°C), you may have to idle the engine
longer. Should the uid level be low during this cold
check, you must check the uid hot before adding uid.
Checking the uid hot will give you a more accurate
reading of the uid level.
5-28

Notice:Too much or too little uid can damage your
transmission. Too much can mean that some of the
uid could come out and fall on hot engine part or
exhaust system parts, starting a re. Too little uid
could cause the transmission to overheat. Be sure to
get an accurate reading if you check your
transmission uid.
Wait at least 30 minutes before checking the
transmission uid level if you have been driving:
When outside temperatures are above 90°F (32°C).
At high speed for quite a while.
In heavy traffic — especially in hot weather.
While pulling a trailer.
Checking the Fluid Level
Prepare your vehicle as follows:
1. Park your vehicle on a level place. Keep the engine
running.
2. With the parking brake applied, place the shift lever
in PARK (P).3. With your foot on the brake pedal, run the engine for
at least once minute and shift to DRIVE (D). Then
shift to NEUTRAL (N) and then REVERSE (R) to ll
the hydraulic system. Then, position the shift lever in
PARK (P).
4. Allow the engine to run at idle (500–800 rpm).
Slowly release the brake pedal.
Then, without shutting off the engine, follow these steps:
Cold Check Procedure
The purpose of the cold check is to determine if the
transmission has enough uid to be operated safely until
a hot check can be made. The uid level rises as uid
temperature increases. Do not ll above the COLD
CHECK band if the transmission uid is below normal
operating temperatures.
1. Pull out the dipstick and wipe it with a clean rag or
paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again.
3. Check the uid level reading. Repeat the check
procedure to verify the reading.
5-31

How to Add Automatic
Transmission Fluid
Refer to the Maintenance Schedule to determine what
kind of transmission uid to use. SeeRecommended
Fluids and Lubricants (Gasoline Engine) on page 6-14.
Add uid only after checking the transmission uid
while it is hot. A cold check is used only as a reference.
If the uid level is low, add only enough of the proper
uid to bring the level up to the HOT area for a hot
check. It does not take much uid, generally less than
one pint (0.5 L). Do not overll.
Notice:Use of the incorrect automatic transmission
uid may damage your vehicle, and the damages
may not be covered by your warranty. Always use the
automatic transmission uid listed inRecommended
Fluids and Lubricants (Gasoline Engine) on
page 6-14.
After adding uid, recheck the uid level as described
under “How to Check Automatic Transmission Fluid,”
earlier in this section.
When the correct uid level is obtained, push the
dipstick back in all the way.
Manual Transmission Fluid
When to Check Manual
Transmission Fluid
A good time to have your manual transmission uid
checked is when the engine oil is changed. See
Additional Required Services (Gasoline Engine)
on page 6-7to nd out when to change your
transmission uid.
How to Check Manual
Transmission Fluid
Because this operation can be a little difficult, you may
choose to have this done at the dealership service
department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading.
Notice:Too much or too little uid can damage your
transmission. Too much can mean that some of the
uid could come out and fall on hot engine part or
exhaust system parts, starting a re. Too little uid
could cause the transmission to overheat. Be sure
to get an accurate reading if you check your
transmission uid.
5-33

When to Check and What to Use
The clutch master cylinder
reservoir is located in
the rear of the engine
compartment on the
driver’s side of the vehicle.
SeeEngine Compartment
Overview on page 5-14
for more information on
location.
Refer to the Maintenance Schedule to determine how
often you should check the uid level in your clutch
master cylinder reservoir and for the proper uid.
SeeOwner Checks and Services on page 6-11and
Recommended Fluids and Lubricants (Gasoline Engine)
on page 6-14.
How to Check and Add Fluid
The proper uid should be added if the level does not
reach the bottom of the diaphragm when it is in place in
the reservoir. See the instructions on the reservoir cap.
Engine Coolant
The cooling system in your vehicle is lled with
DEX-COOL®engine coolant. This coolant is designed
to remain in your vehicle for ve years or 150,000 miles
(240 000 km), whichever occurs rst, if you add only
DEX-COOL
®extended life coolant.
The following explains your cooling system and how
to add coolant when it is low. If you have a problem
with engine overheating, seeEngine Overheating
on page 5-37.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
®coolant will:
Give freezing protection down to−34°F (−37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
Let the warning lights and gages work as they
should.
Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core, or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at the rst maintenance
service after each 25,000 miles (41 500 km) or
24 months, whichever occurs rst. Any repairs
would not be covered by your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your vehicle.
5-35