2007 CHEVROLET AVALANCHE engine overheat

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.
This message displays along with a continuous
chime if the transmission uid in the vehicle
gets hot. 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 clears
and the chime stops when the uid temperature
reaches a safe level.
TURN SIGNAL ON
This message displays and a chime sounds if a
turn signal is left on for 3/4 of a mile (1.2 km).
Move the turn signal/multifunction lever to the
off position.
WASHER FLUID LOW ADD FLUID
This message displays when the windshield
washer uid is low. Fill the windshield washer uid
reservoir as soon as possible. SeeEngine
Compartment Overview on page 444for the
location of the windshield washer uid reservoir.
Also, seeWindshield Washer Fluid on page 470
for more information.
277

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). This is called “free-wheeling.”
The brakes will have to do all the work
and could overheat and fade.
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Then, shut the engine off and close the window
almost all the way to preserve the heat. Start
the engine again and repeat this only when you
feel really uncomfortable from the cold. But do it as
little as possible. Preserve the fuel as long as
you can. To help keep warm, you can get out of
the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.
If Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow
In order to free your vehicle when it is stuck, you
need to spin the wheels, but you do not want to spin
the 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 vehicle’s tires spin at
high speed, they can explode, and
you or others could be injured.
CAUTION: (Continued)
CAUTION: (Continued)
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 the wheels can destroy parts
of your vehicle as well as the tires. If you
spin the wheels too fast while shifting the
transmission back and forth, you can destroy
the transmission.
For information about using tire chains on your
vehicle, seeTire Chains on page 514.
Rocking Your Vehicle to Get It Out
First, turn the steering wheel left and right. That
will clear the area around the front wheels.
If you have a four-wheel-drive vehicle, shift into
Four-Wheel High. Turn the StabiliTrak
®System off.
400

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.
You can tow in DRIVE (D). 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
at higher altitudes will boil at a lower temperature
than at or near sea level. 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, seeEngine Overheating on page 460.
Parking on Hills
{CAUTION:
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.
424

Service........................................................ 432
Accessories and Modications................... 433
California Proposition 65 Warning.............. 433
Doing Your Own Service Work.................. 434
Adding Equipment to the Outside
of Your Vehicle...................................... 435
Fuel............................................................. 435
Gasoline Octane........................................ 436
Gasoline Specications.............................. 436
California Fuel........................................... 436
Additives................................................... 437
Fuel E85 (85% Ethanol)............................ 438
Fuels in Foreign Countries........................ 439
Filling the Tank......................................... 440
Filling a Portable Fuel Container............... 442
Checking Things Under the Hood.............. 442
Hood Release........................................... 443
Engine Compartment Overview.................. 444
Engine Oil................................................. 446
Engine Oil Life System.............................. 449Engine Air Cleaner/Filter............................ 451
Automatic Transmission Fluid.................... 454
Engine Coolant.......................................... 457
Coolant Surge Tank Pressure Cap............ 460
Engine Overheating................................... 460
Overheated Engine Protection
Operating Mode..................................... 463
Cooling System......................................... 464
Engine Fan Noise..................................... 469
Power Steering Fluid ................................. 469
Windshield Washer Fluid........................... 470
Brakes...................................................... 472
Battery...................................................... 475
Jump Starting............................................ 476
Rear Axle.................................................... 482
Four-Wheel Drive........................................ 483
Front Axle................................................... 484
Headlamp Aiming........................................ 485
Section 5 Service and Appearance Care
429

Automatic Transmission Fluid
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 on page 566, and
be sure to use the transmission uid listed in
Recommended Fluids and Lubricants on page 574.
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 parts 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).
454

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 460.
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.
What to Use
Use a mixture of one-half clean, drinkable water
and one-half DEX-COOL®coolant which will
not damage aluminum parts. If you use this coolant
mixture, you do not need to add anything else.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can
boil before the proper coolant mixture will.
Your vehicle’s coolant warning system is
set for the proper coolant mixture. With
plain water or the wrong mixture, your
engine could get too hot but you would
not get the overheat warning. Your engine
could catch re and you or others could
be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.
458

Notice:If you use an improper coolant
mixture, your engine could overheat and be
badly damaged. The repair cost would not be
covered by your warranty. Too much water
in the mixture can freeze and crack the engine,
radiator, heater core, and other parts.
If you have to add coolant more than four times a
year, have your dealer check your cooling system.
Notice:If you use extra inhibitors and/or
additives in your vehicle’s cooling system,
you could damage your vehicle. Use only
the proper mixture of the engine coolant
listed in this manual for the cooling system.
SeeRecommended Fluids and Lubricants
on page 574for more information.
Checking Coolant
The coolant surge tank is located in the engine
compartment on the passenger’s side of the
vehicle. SeeEngine Compartment Overview
on page 444for more information on location.
{CAUTION:
Turning the surge tank pressure cap when
the engine and radiator are hot can allow
steam and scalding liquids to blow out
and burn you badly. Never turn the surge
tank pressure cap — even a little — when
the engine and radiator are hot.
The vehicle must be on a level surface. When
your engine is cold, the coolant level should be
at the FULL COLD mark.
If your vehicle is equipped with a low coolant
sensor and the LOW COOLANT LEVEL message
comes on and stays on, it means you are low
on engine coolant. See “LOW COOLANT LEVEL”
underDIC Warnings and Messages on page 267.
459