2007 GMC SIERRA CLASSIC heating

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

Driving with a Trailer
{CAUTION:
If you have a rear-most window open and
you pull a trailer with your vehicle, carbon
monoxide (CO) could come into your
vehicle. You cannot see or smell CO. It
can cause unconsciousness or death. See
Engine Exhaust on page 174. To maximize
your safety when towing a trailer:
Have your exhaust system inspected
for leaks, and make necessary repairs
before starting on your trip.
Keep the rear-most windows closed.
CAUTION: (Continued)
CAUTION: (Continued)

If exhaust does come into your vehicle
through a window in the rear or
another opening, drive with your front,
main heating or cooling system on
and with the fan on any speed. This
will bring fresh, outside air into your
vehicle. Do not use the climate control
setting for maximum air because it
only recirculates the air inside your
vehicle. SeeClimate Control System
on page 230.
Towing a trailer requires a certain amount of
experience. Before setting out for the open road,
you’ll want to get to know your rig. Acquaint
yourself with the feel of handling and braking with
the added weight of the trailer. And always
keep in mind that the vehicle you are driving is
now a good deal longer and not nearly as
responsive as your vehicle is by itself.
451

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

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 505.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
30,000 miles (50 000 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.
502

Adding Coolant
If you need more coolant, add the proper
DEX-COOL®coolant mixture at the surge tank,
but only when the engine is cool. SeeCooling
System on page 508.
{CAUTION:
You can be burned if you spill coolant
on hot engine parts. Coolant contains
ethylene glycol, and it will burn if the
engine parts are hot enough. Do not spill
coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight and fully seated.
Coolant Surge Tank Pressure Cap
Notice:If the pressure cap is not tightly
installed, coolant loss and possible engine
damage may occur. Be sure the cap is properly
and tightly secured.
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 480for more
information on location.
Engine Overheating
You will nd a coolant temperature gage on your
vehicle’s instrument panel. SeeEngine Coolant
Temperature Gage on page 256.
In addition, you will nd an ENGINE
OVERHEATED and a REDUCED ENGINE
POWER message in the Driver Information
Center (DIC) on the instrument panel. SeeDIC
Warnings and Messages on page 270.
505

A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Cooling Fan
{CAUTION:
An electric fan under the hood can start up
and injure you even when the engine is not
running. Keep hands, clothing, and tools
away from any underhood electric fan.
If the coolant inside the coolant surge tank is
boiling, do not do anything else until it cools down.
The vehicle should be parked on a level surface.
Check the coolant level after the system cools
down. Some amount of coolant may be lost due to
overheating.
All Other Engines
509

Tires
Your new vehicle comes with high-quality tires
made by a leading tire manufacturer. If you ever
have questions about your tire warranty and where
to obtain service, see your GM Warranty booklet
for details. For additional information refer to
the tire manufacturer’s booklet included with your
vehicle.
{CAUTION:
Poorly maintained and improperly used
tires are dangerous.
Overloading your vehicle’s tires can
cause overheating as a result of too
much friction. You could have an
air-out and a serious accident. See
Loading Your Vehicle on page 409.
CAUTION: (Continued)
CAUTION: (Continued)

Underinated tires pose the
samedanger as overloaded tires. The
resulting accident could cause serious
injury. Check all tires frequently to
maintain the recommended pressure.
Tire pressure should be checked when
your vehicle’s tires are cold. See
Inflation - Tire Pressure on page 551.
Overinated tires are more likely
to be cut, punctured, or broken by a
sudden impact — such as when
you hit a pothole. Keep tires at the
recommended pressure.
Worn, old tires can cause accidents.
If the tire’s tread is badly worn, or
if your vehicle’s tires have been
damaged, replace them.
543