If No Steam Is Coming From Your
Engine
The ENGINE OVERHEATED STOP ENGINE or
the ENGINE OVERHEATED IDLE ENGINE
message, along with a low coolant condition, can
indicate a serious problem.
If you get an engine overheat warning, but see or
hear no steam, the problem may not be too
serious. Sometimes the engine can get a little too
hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. SeeTowing a Trailer on
page 447.If you get the ENGINE OVERHEATED STOP
ENGINE or the ENGINE OVERHEATED IDLE
ENGINE message with no sign of steam, try this
for a minute or so:
1. If you have an air conditioner and it is on, turn
it off.
2. Turn on your heater to full hot at the highest
fan speed and open the windows as
necessary.
3. If you are stopped in a traffic jam, apply the
brake, shift to NEUTRAL (N); otherwise, shift to
the highest gear while driving — DRIVE (D) or
THIRD (3).
If you no longer have the overheat warning, you
can drive. Just to be safe, drive slower for
about 10 minutes. If the warning does not come
back on, you can drive normally.
519
If the warning continues, pull over, stop, and park
your vehicle immediately.
If there is still no sign of steam and your vehicle
has an engine-driven cooling fan, push down
the accelerator until the engine speed is about
twice as fast as normal idle speed for at least
ve minutes while you are parked.
If there is still no sign of steam and your vehicle
has an electric cooling fan, idle the engine for
ve minutes while you are parked.
If you still have the warning, turn off the engine
and get everyone out of the vehicle until it
cools down. Also, see “Overheated Engine
Protection Operating Mode” later in this section.
You may decide not to lift the hood but to get
service help right away.Overheated Engine Protection
Operating Mode (V8 Engines Only)
If an overheated engine condition exists and
the REDUCED ENGINE POWER message
is displayed, an overheat protection mode which
alternates ring groups of cylinders helps
prevent engine damage. In this mode, you will
notice a loss in power and engine performance.
This operating mode allows your vehicle to
be driven to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in
the overheat protection mode should be avoided.
Notice:After driving in the overheated
engine protection operating mode, to avoid
engine damage, allow the engine to cool before
attempting any repair. The engine oil will be
severely degraded. Repair the cause of coolant
loss, change the oil and reset the oil life
system. SeeEngine Oil (Gasoline Engine) on
page 502.
520
Cooling System
If your vehicle has the DURAMAX®Diesel engine,
see the DURAMAX®Diesel manual for more
information.
When you decide it is safe to lift the hood, here is
what you will see:
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Cooling Fan
{CAUTION:
An electric engine cooling fan can start
even when the engine is not running.
To avoid injury, always keep hands,
clothing, and tools away from any engine
cooling 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.
5.3L Engine (4.3L, 4.8L and 6.0L Similar)
521
The coolant level should be at or above the FULL
COLD mark. If it is not, you may have a leak at
the pressure cap or in the radiator hoses,
heater hoses, radiator, water pump, or somewhere
else in the cooling system.
{CAUTION:
Heater and radiator hoses, and other
engine parts, can be very hot. Do not touch
them. If you do, you can be burned.
Do not run the engine if there is a leak. If
you run the engine, it could lose all
coolant. That could cause an engine re,
and you could be burned. Get any leak
xed before you drive the vehicle.
Notice:Engine damage from running your
engine without coolant is not covered by your
warranty. SeeOverheated Engine Protection
Operating Mode (V8 Engines Only) on page 520
for information on driving to a safe place in an
emergency.
522
{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 a proper coolant.
Notice:In cold weather, water can freeze and
crack the engine, radiator, heater core and
other parts. Use the recommended coolant and
the proper coolant mixture.
{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.
1. Remove the coolant
surge tank pressure
cap when the
cooling system,
including the coolant
surge tank
pressure cap and
upper radiator hose,
is no longer hot.
Turn the pressure cap slowly counterclockwise
about one full turn. If you hear a hiss, wait
for that to stop. A hiss means there is
still some pressure left.
524
Door (cont.)
Rear Door Security Locks........................ 122
Rear Doors.............................................. 123
Driver
Position, Safety Belt................................... 28
Driver Information Center (DIC)................... 269
DIC Operation and Displays............270, 277
DIC Vehicle Customization....................... 291
DIC Warnings and Messages................... 281
Driving
At Night................................................... 409
City.......................................................... 414
Defensive................................................. 376
Drunken................................................... 377
Freeway................................................... 415
Hill and Mountain Roads.......................... 418
In Rain and on Wet Roads...................... 410
Off-Road.................................................. 392
Recovery Hooks....................................... 426
Rocking Your Vehicle to Get it Out.......... 425
Winter...................................................... 420
Dual Automatic Climate Control System....... 240
Dual Tire Operation..................................... 562
DVD
Rear Seat Entertainment System............. 357E
Electrical System
Add-On Equipment................................... 611
Center Instrument Panel Fuse Block........ 614
Fuses and Circuit Breakers...................... 612
Instrument Panel Fuse Block................... 612
Power Windows and Other Power
Options................................................. 611
Underhood Fuse Block............................. 615
Windshield Wiper Fuses........................... 611
Engine
Air Cleaner/Filter...................................... 507
Check and Service Engine Soon Light..... 262
Coolant.................................................... 514
Coolant Heater......................................... 138
Coolant Temperature Gage...................... 260
Drive Belt Routing.................................... 643
Engine Compartment Overview................ 500
Exhaust................................................... 169
Fan Noise................................................ 526
Oil ........................................................... 502
Oil Life System........................................ 505
Overheated Protection Operating Mode.... 520
Overheating............................................. 517
Starting.................................................... 136
673
N
Navigation/Radio System, see Navigation
Manual..................................................... 357
New Vehicle Break-In.................................. 134
Noise Control System, Tampering................ 544
Normal Maintenance Replacement Parts..... 642
O
Odometer.................................................... 250
Odometer, Trip............................................ 250
Off-Road Driving.......................................... 392
Off-Road Recovery...................................... 389
Oil
Engine..................................................... 502
Pressure Gage......................................... 265
Pressure Light.......................................... 266
Oil, Engine Oil Life System......................... 505
Older Children, Restraints............................. 46
Online Owner Center................................... 651
OnStar
®System, see OnStar®Manual........ 182
Operation, Universal Home Remote
System............................................187, 191
Other Warning Devices................................ 213
Outlet Adjustment........................................ 247Outlets
Accessory Power..................................... 234
Outside
Manual Mirrors......................................... 176
Power Foldaway Mirrors........................... 179
Power Mirrors.......................................... 178
Trailer-Tow Mirrors................................... 177
Overheated Engine Protection Operating
Mode....................................................... 520
Owner Checks and Services....................... 635
Owners, Canadian.......................................... 3
P
Paint, Damage............................................ 608
Park Aid...................................................... 230
Park (P)
Shifting Into............................................. 165
Shifting Out of......................................... 167
Parking
Assist....................................................... 230
Brake....................................................... 164
Over Things That Burn............................ 168
Passenger Airbag Status Indicator............... 254
Passenger Sensing System........................... 99
678