2008 HUMMER H3 engine overheat

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.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there is still no sign of steam, idle the engine for
three minutes while you are parked. Push down
the accelerator until the engine speed is about twice as
fast as normal idle speed for at least three 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.
You may decide not to lift the hood but to get service
help right away.Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Coolant Recovery Tank
B. Engine Cooling Fan
C. Radiator Pressure Cap
If the coolant inside the coolant recovery tank is boiling,
do not do anything else until it cools down. The
vehicle should be parked on a level surface.3.7L Engine shown, 5.3L Engine similar
5-31

How to Add Coolant to the Coolant
Recovery Tank
If you have not found a problem yet, but the coolant
level is not at the FULL COLD mark, add a 50/50
mixture of clean, drinkable water and DEX-COOL
®
engine coolant at the coolant recovery tank. SeeEngine
Coolant on page 5-27for more information.
{CAUTION:
Adding only plain water to the cooling system
can be dangerous. Plain water, or some other
liquid such as alcohol, can boil before the
proper coolant mixture will. The vehicle’s
coolant warning system is set for the proper
coolant mixture. With plain water or the wrong
mixture, the engine could get too hot but you
would not get the overheat warning. The
engine could catch re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®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.
When the coolant in the coolant recovery tank is at the
FULL COLD mark, start your vehicle.
5-33

If the overheat warning continues, there is one more
thing you can try. Add the proper mixture directly to the
radiator, but be sure the cooling system is cool before
you do it.
{CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the radiator
pressure cap — even a little — they can come
out at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap, is hot. Wait for the cooling system and
radiator pressure cap to cool if you ever have
to turn the pressure cap.
How to Add Coolant to the Radiator
1. Remove the radiator pressure cap when the cooling
system, including the 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.
2. Keep turning the cap to remove it.
3. Fill the radiator with the proper DEX-COOL
®
coolant mixture, up to the base of the ller
neck. SeeEngine Coolant on page 5-27for more
information about the proper coolant mixture.
5-34

Engine Identication
The eighth character in the VIN is the engine code.
This code helps you identify your vehicle’s engine,
specications, and replacement parts. SeeCapacities
and Specifications on page 5-107for your vehicle’s
engine code.
Service Parts Identication Label
This label is on the inside of the glove box. It is
very helpful if you ever need to order parts. The label
has the following information:
Vehicle Identication Number (VIN)
Model designation
Paint information
Production options and special equipment
Do not remove this label from the vehicle.
Electrical System
Add-On Electrical Equipment
Notice:Do not add anything electrical to your
vehicle unless you check with your dealer/retailer
rst. Some electrical equipment can damage your
vehicle and the damage would not be covered by
your warranty. Some add-on electrical equipment can
keep other components from working as they should.
Add-on equipment can drain your vehicle’s battery, even
if your vehicle is not operating.
Your vehicle has an airbag system. Before attempting to
add anything electrical to your vehicle, seeServicing
Your Airbag-Equipped Vehicle on page 1-67.
Windshield Wiper Fuses
The windshield wiper motor is protected by a circuit
breaker and a fuse. If the motor overheats due to heavy
snow, etc., the wiper will stop until the motor cools. If
the overload is caused by some electrical problem,
have it xed.
5-101

D
Daytime Running Lamps..................................3-17
Defensive Driving............................................. 4-2
Doing Your Own Service Work........................... 5-4
Dome Lamp...................................................3-19
Dome Lamp Override......................................3-20
Door
Locks.......................................................... 2-7
Power Door Locks......................................... 2-8
Programmable Automatic Door Locks............... 2-8
Rear Door Security Locks............................... 2-9
Driver Information Center (DIC).........................3-40
DIC Operation and Displays..........................3-40
DIC Warnings and Messages........................3-43
Driving
At Night.....................................................4-32
Before a Long Trip......................................4-34
Defensive..................................................... 4-2
Drunken....................................................... 4-2
Highway Hypnosis.......................................4-34
Hill and Mountain Roads..............................4-34
In Rain and on Wet Roads...........................4-33
Off-Road....................................................4-12
Recovery Loops..........................................4-40
Rocking Your Vehicle to Get it Out.................4-40
Winter........................................................4-35
E
EDR .............................................................7-16
Electrical System
Add-On Equipment.....................................5-101
Engine Compartment Fuse Block.................5-103
Fuses and Circuit Breakers.........................5-102
Power Windows and Other Power Options....5-102
Windshield Wiper Fuses.............................5-101
Engine
Air Cleaner/Filter.........................................5-20
Check and Service Engine Soon Light............3-36
Coolant......................................................5-27
Coolant Heater............................................2-22
Coolant Temperature Gage...........................3-35
Drive Belt Routing.......................................6-15
Engine Compartment Overview......................5-12
Exhaust.....................................................2-36
Fan Noise..................................................5-36
Oil .............................................................5-15
Oil Life System...........................................5-18
Overheating................................................5-29
Running While Parked..................................2-37
Starting......................................................2-20
Event Data Recorders.....................................7-17
Exit Lighting...................................................3-20
Extender, Safety Belt.......................................1-30
Exterior Lamps...............................................3-15
4