2007 GMC SIERRA CLASSIC overheating

Certain power accessory plugs may not be
compatible to the accessory power outlet and
could result in blown vehicle or adapter fuses.
If you experience a problem, see your dealer for
additional information on the accessory power
plugs.
Notice:Adding any electrical equipment to
your vehicle may damage it or keep other
components from working as they should.
The repairs would not be covered by your
warranty. Do not use equipment exceeding
maximum amperage rating of 20 amperes.
Check with your dealer before adding electrical
equipment.
When adding electrical equipment, be sure to
follow the proper installation instructions included
with the equipment.
Notice:Improper use of the power outlet can
cause damage not covered by your warranty.
Do not hang any type of accessory or
accessory bracket from the plug because the
power outlets are designed for accessory
power plugs only.Ashtray(s) and Cigarette Lighter
Your vehicle may have a front ashtray located near
the center of the instrument panel. Pull on the
door to open it.
Notice:If you put papers, pins, or other
ammable items in the ashtray, hot cigarettes
or other smoking materials could ignite
them and possibly damage your vehicle. Never
put ammable items in the ashtray.
To remove the front ashtray, pull the ashtray
toward you. To replace the ashtray, place
the ashtray on the slides at the side of its location
in the instrument panel. To use the cigarette
lighter, push it in all the way, and let go. When it
is ready, the lighter will pop back out by itself.
Notice:Holding a cigarette lighter in while it
is heating will not allow the lighter to back
away from the heating element when it is hot.
Damage from overheating may occur to the
lighter or heating element, or a fuse could be
blown. Do not hold a cigarette lighter in
while it is heating.
229

The ABS warning light should come on briey
when you turn the ignition key to RUN. If the light
does not come on then, have it xed so it will
be ready to warn you if there is a problem.
Traction Off Light
If your vehicle has the
Traction Assist System,
this light should
come on briey when
you turn the ignition
to RUN.
If the light does not come on then, the system
may require service. Have it xed so it will be there
to warn you if the system is turned off.
If the light stays on, or comes on when you are
driving, there may be a problem with your Traction
Assist System and your vehicle may need
service. When this light is on, the system will not
limit wheel spin. Adjust your driving accordingly.
Engine Coolant Temperature Gage
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 uctuate 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.
SeeEngine Overheating on page 505.
United StatesCanada
256

DRIVER DOOR AJAR
If the driver’s door is not fully closed, this message
will appear on the display and you will hear a
chime. Stop and turn off the vehicle, check
the door for obstructions, and close the door again.
Check to see if the message still appears on the
DIC. Pressing any of the four DIC buttons will
acknowledge the message and clear it from the
DIC display. If your vehicle does not have the four
DIC buttons, pressing the trip odometer reset
stem will acknowledge the message and clear it
from the DIC display.
ENGINE COOLANT HOT
If the cooling system temperature gets hot, this
message will appear in the DIC. Turn off the
air conditioning. If the message is still on, or if the
engine coolant temperature gage continues to
rise, pull the vehicle over when it is safe to do so.
SeeEngine Coolant Temperature Gage on
page 256for more information. Stop the vehicle
and let the engine idle in PARK (P) for a few
minutes, or NEUTRAL with the parking brake set
for manual transmissions, to allow the coolant
to reach a safe temperature. This message
will clear when the coolant temperature drops to
safe operating temperature.
ENGINE OVERHEATED
Notice:If you drive your vehicle while the
engine is overheating, severe engine damage
may occur. If an overheat warning appears
on the instrument panel cluster and/or
DIC, stop the vehicle as soon as possible.
Do not increase the engine speed above
normal idling speed. SeeEngine Overheating
on page 505for more information.
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 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.
273

PASSENGER DOOR AJAR
If the passenger’s door is not fully closed, this
message will appear on the display and you will
hear a chime. Stop and turn off the vehicle, check
the door for obstructions, and close the door
again. Check to see if the message still appears
on the DIC. Pressing any of the four DIC
buttons will acknowledge the message and clear it
from the DIC display. If your vehicle does not
have the four DIC buttons, pressing the trip
odometer reset stem will acknowledge the
message and clear it from the DIC display.
RANGE SHIFT INHIBITED
(Allison Transmission®Only)
If the transmission is unable to shift into a selected
gear, this message will appear on the DIC. The
electronic shift position indicator on the instrument
panel cluster may blink when this occurs. To
make the vehicle shift to the requested gear, you
may have to shift back to PARK (P) or
NEUTRAL (N) and re-select the desired gear.
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.
SeeEngine Overheating on page 505for further
information.
This message will also display when the vehicle’s
engine power is reduced. Reduced engine
power can affect the vehicle’s ability to accelerate.
If this message is on, but there is no reduction
in performance, proceed to your destination. The
performance may be reduced the next time
the vehicle is driven. The vehicle may be driven at
a reduced speed while this message is on, but
acceleration and speed may be reduced. Anytime
this message stays on, the vehicle should be
taken to your dealer for service as soon as
possible.
276

TRANSMISSION HOT
Notice:If you drive your vehicle while the
transmission uid is overheating and the
transmission temperature warning is displayed
on the instrument panel cluster and/or DIC,
you can damage the transmission. This could
lead to costly repairs that would not be
covered by your warranty. Do not drive your
vehicle with overheated transmission uid
or while the transmission temperature warning
is displayed.
If the transmission uid temperature becomes
high, this message will appear on the DIC display.
When the transmission enters the protection
mode, you may notice a change in the
transmission shifting patterns. When the
transmission uid temperature returns to normal,
the display will turn off and the transmission
shifting patterns will return to normal.If the vehicle has the Tow/Haul mode, use this
feature if the transmission is operating at higher
temperatures and/or the following situations
exist, which can cause the transmission to operate
at higher temperatures:
Towing a trailer
Hot outside air temperatures
Hauling a large or heavy load
Over-loading
Low transmission uid level
High transmission uid level
Restricted air ow to the radiator and the
auxiliary transmission oil cooler
A temporary solution to hotter transmission
operating temperatures may be to let the
transmission cool down. If the transmission is
operated at higher temperatures on a frequent
basis, seeScheduled Maintenance (Gasoline
Engine) on page 617for the transmission
your vehicle is equipped with for the proper
transmission maintenance intervals. Also see
Transmission Temperature Gage on page 257for
more information.
280

TRANS (Transmission) HOT IDLE
ENGINE
Notice:If you drive your vehicle while the
transmission uid is overheating and the
transmission temperature warning is displayed
on the instrument panel cluster and/or DIC,
you can damage the transmission. This could
lead to costly repairs that would not be
covered by your warranty. Do not drive your
vehicle with overheated transmission uid
or while the transmission temperature warning
is displayed.
If the transmission uid in the vehicle gets hot, this
message will appear on the DIC along with a
continuous chime. Driving with the transmission
uid temperature high can cause damage to
the vehicle. Stop the vehicle and let it idle to allow
the transmission to cool. This message will
clear and the chime will stop when the uid
temperature reaches a safe level. See
Transmission Temperature Gage on page 257.
TRANS (Transmission) IN WARM UP
(Allison Transmission®Only)
When temperatures are very cold, the transmission
will prevent certain operations such as shifts to
some ranges and engaging the torque converter
clutch to protect against damage. When active, the
DIC will display the message TRANS IN
WARM UP.
TURN SIGNAL ON
If a turn signal is left on for 3/4 of a mile (1.2 km),
this message will appear on the display and
you will hear a chime. Move the turn
signal/multifunction lever to the off position.
Pressing any of the four DIC buttons will
acknowledge the message and clear it from the
DIC display. If your vehicle does not have the
four DIC buttons, pressing the trip odometer reset
stem will acknowledge the message and clear
it from the DIC display.
281

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 gearbefore
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.
If you have an automatic transmission, you can
tow in DRIVE (D). You may want to shift the
transmission to 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 264.
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).
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 a few 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 a few minutes before
turning the engine off. If you do get the overheat
warning, seeEngine Overheating on page 505.
453

Service........................................................ 468
Accessories and Modications................... 468
California Proposition 65 Warning.............. 469
Doing Your Own Service Work.................. 469
Adding Equipment to the Outside of
Your Vehicle.......................................... 470
Fuel............................................................. 470
Gasoline Octane........................................ 470
Gasoline Specications.............................. 471
California Fuel........................................... 471
Additives................................................... 472
Fuel E85 (85% Ethanol)............................ 473
Fuels in Foreign Countries........................ 474
Filling the Tank......................................... 474
Filling a Portable Fuel Container............... 477
Checking Things Under the Hood.............. 478
Hood Release........................................... 479
Engine Compartment Overview.................. 480
Engine Oil (Gasoline Engine).................... 486
Engine Oil Life System
(Gasoline Engine).................................. 489
Engine Air Cleaner/Filter
(Gasoline Engines)................................. 491Automatic Transmission Fluid
(Allison Transmission®) .......................... 494
Automatic Transmission Fluid
(Except Allison Transmission
®) ............... 497
Manual Transmission Fluid........................ 500
Hydraulic Clutch........................................ 501
Engine Coolant.......................................... 502
Coolant Surge Tank Pressure Cap............ 505
Engine Overheating................................... 505
Overheated Engine Protection
Operating Mode (V8 Engines Only)........ 508
Cooling System......................................... 508
Engine Fan Noise..................................... 514
Power Steering Fluid ................................. 515
Windshield Washer Fluid........................... 516
Brakes...................................................... 517
Battery...................................................... 520
Jump Starting............................................ 521
Rear Axle.................................................... 527
Four-Wheel Drive........................................ 528
Front Axle................................................... 529
Section 5 Service and Appearance Care
465