2009 HUMMER H3 engine

Cooling System
The cooling system allows the
engine to maintain the correct
working temperature.
A. Coolant Recovery Tank
B. Engine Cooling Fan
C. Radiator Pressure CapA. Coolant Recovery Tank
B. Radiator Pressure Cap
C. Engine Cooling Fan
{CAUTION
An electric engine cooling fan
under the hood can start up even
when the engine is not running and
can cause injury. Keep hands,
clothing, and tools away from any
underhood electric fan.
{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:Using coolant other
than DEX-COOL
®can cause
premature engine, heater core, or
radiator corrosion. In addition,
the engine coolant could require
changing sooner, at 30,000 miles
(50 000 km) or 24 months,
whichever occurs rst. Any
repairs would not be covered by
the vehicle warranty. Always
use DEX-COOL
®(silicate-free)
coolant in the vehicle. 3.7L Engine
5.3L Engine
5-22 Service and Appearance Care

Engine Coolant
The cooling system in the vehicle
is lled with DEX-COOL®engine
coolant. This coolant is designed to
remain in the vehicle for ve years
or 150,000 miles (240 000 km),
whichever occurs rst.
The following explains the cooling
system and how to check and
add coolant when it is low.
If there is a problem with engine
overheating, seeEngine
Overheating on page 5-27.
What to Use
{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.
(Continued)
CAUTION (Continued)
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.
Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
coolant. If using this mixture,
nothing else needs to be added.
This mixture:
Gives freezing protection down
to−34°F (−37°C), outside
temperature.
Gives boiling protection up to
265°F (129°C), engine
temperature.
Protects against rust and
corrosion.
Will not damage aluminum parts.
Helps keep the proper engine
temperature.
Notice:If an improper coolant
mixture is used, the engine could
overheat and be badly damaged.
The repair cost would not be
covered by the vehicle warranty.
Too much water in the mixture
can freeze and crack the engine,
radiator, heater core, and
other parts.
Notice:If extra inhibitors
and/or additives are used in the
vehicle’s cooling system, the
vehicle could be damaged.
Use only the proper mixture of
the engine coolant listed in
this manual for the cooling
system. SeeRecommended
Fluids and Lubricants on
page 6-12for more information.
Service and Appearance Care 5-23

Checking Coolant
The vehicle must be on a level
surface when checking the
coolant level.
The coolant recovery tank cap has
this symbol on it.
It is located toward the rear of
the engine compartment on
the passenger side of the vehicle.
SeeEngine Compartment Overview
on page 5-10for more information
on location.
Check to see if coolant is visible in
the coolant recovery tank. If the
coolant inside the coolant recovery
tank is boiling, do not do anythingelse until it cools down. If coolant is
visible but the coolant level is not
at or above the FULL COLD
mark, add a 50/50 mixture of clean,
drinkable water and DEX-COOL
coolant at the coolant recovery tank,
but be sure the cooling system is
cool before this is done.
The vehicle must be on a level
surface. When the engine is cold,
the coolant level should be at FULL
COLD, or a little higher. When
the engine is warm, the level could
be above the FULL COLD level.
When the engine is cold, the coolant
level should be at least up to the
FULL COLD mark. If it is not, there
could be a leak in the cooling
system.
How to Add Coolant to the
Recovery Tank
{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.
Notice:This vehicle has a
specic coolant ll procedure.
Failure to follow this procedure
could cause the engine to
overheat and be severely
damaged.
When the coolant in the coolant
recovery tank is at the FULL COLD
mark, start the vehicle.
If coolant is needed, add the proper
DEX-COOL coolant mixture at
the coolant recovery tank.
5-24 Service and Appearance Care

How to Add Coolant to the
Radiator
{CAUTION
An electric engine cooling fan
under the hood can start up even
when the engine is not running and
can cause injury. Keep hands,
clothing, and tools away from any
underhood electric fan.
{CAUTION
Steam and scalding liquids
from a hot cooling system can
blow out and burn you badly.
(Continued)
CAUTION (Continued)
They are under pressure, and if
you turn the surge tank pressure
cap — even a little — they can
come out at high speed.
Never turn the cap when the
cooling system, including the
surge tank pressure cap, is hot.
Wait for the cooling system and
surge tank pressure cap to cool
if you ever have to turn the
pressure cap.
If coolant is needed, add the proper
mixture directly to the radiator,
but be sure the cooling system is
cool before this is done.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.
Service and Appearance Care 5-25

3. Fill the radiator with the proper
DEX-COOL coolant mixture, up
to the base of the ller neck.
SeeEngine Coolant on
page 5-23for more information
about the proper coolant mixture.
4. Fill the coolant recovery tank to
the FULL COLD mark.5. Reinstall the cap on the coolant
recovery tank, but leave the
radiator pressure cap off.
6. Start the engine and let it run
until you can feel the upper
radiator hose getting hot. Watch
out for the engine cooling fan.7. By this time, the coolant level
inside the radiator ller neck
might be lower. If the level
is lower, add more of the proper
DEX-COOL coolant mixture
through the ller neck until the
level reaches the base of the
ller neck.
8. Then replace the pressure cap.
At any time during this procedure
if coolant begins to ow out of
the ller neck, reinstall the
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.
5-26 Service and Appearance Care

Engine Overheating
The vehicle has an indicator to warn
of engine overheating.
A coolant temperature gage is
displayed on the instrument panel.
SeeEngine Coolant Temperature
Gage on page 3-29.
You may decide not to lift the hood
when this warning appears, but
instead get service help right away.
SeeRoadside Service on page 7-6.
If you do decide to lift the hood,
make sure the vehicle is parked on
a level surface.
Then check to see if the engine
cooling fans are running. If the
engine is overheating, both fans
should be running. If they are not, do
not continue to run the engine and
have the vehicle serviced.The air conditioning might stop
working if the engine is too hot.
This is normal and helps cool the
engine.
Notice:Engine damage from
running the engine without
coolant is not covered by the
warranty.
Notice:If the engine catches re
because of being driven with
no coolant, your vehicle can be
badly damaged. The costly
repairs would not be covered by
the vehicle warranty.
If Steam Is Coming From The
Engine Compartment
{CAUTION
Steam from an overheated engine
can burn you badly, even if you
just open the hood. Stay away
from the engine if you see or hear
steam coming from it. Just turn it
off and get everyone away from
the vehicle until it cools down.
Wait until there is no sign of
steam or coolant before you
open the hood.
If you keep driving when your
engine is overheated, the liquids
in it can catch re. You or others
could be badly burned. Stop your
engine if it overheats, and get
out of the vehicle until the engine
is cool.
Service and Appearance Care 5-27

If No Steam Is Coming From
The Engine Compartment
If an engine overheat warning is
displayed but no steam can be seen
or heard, the problem may not be
too serious. Sometimes the engine
can get a little too hot when the
vehicle:
Climbs a long hill on a hot day.
Stops after high-speed driving.
Idles for long periods in traffic.
Tows a trailer. See “Driving
on Grades” underTowing a
Trailer on page 4-42.
If the overheat warning is displayed
with no sign of steam:
1. Turn the air conditioning off.
2. Turn the heater on to the highest
temperature and to the highest
fan speed. Open the windows as
necessary.3. In heavy traffic, let the engine idle
in N (Neutral) while stopped. If it
is safe to do so, pull off the road,
shift to P (Park) or N (Neutral) and
let the engine idle.
If the temperature overheat gage is
no longer in the overheat zone
or an overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle
slow for about 10 minutes. Keep a
safe vehicle distance from the
car in front of you. If the warning
does not come back on, continue to
drive normally.
If the warning continues, pull over,
stop, and park the vehicle right away.
If there is no sign of steam, idle the
engine for three minutes while
parked. If the warning is still
displayed, turn off the engine until
it cools down.
Engine Fan Noise
This vehicle has a clutched engine
cooling fan. When the clutch is
engaged, the fan spins faster
to provide more air to cool the
engine. In most everyday driving
conditions, the clutch is not
engaged. This improves fuel
economy and reduces fan noise.
Under heavy vehicle loading,
trailer towing and/or high outside
temperatures, the fan speed
increases when the clutch engages.
So you may hear an increase in
fan noise. This is normal and should
not be mistaken as the transmission
slipping or making extra shifts.
It is merely the cooling system
functioning properly. The fan will
slow down when additional cooling
is not required and the clutch
disengages.
You may also hear this fan noise
when you start the engine. It will go
away as the fan clutch disengages.
5-28 Service and Appearance Care

Power Steering Fluid
SeeEngine Compartment Overview
on page 5-10for reservoir location.
When to Check Power
Steering Fluid
It is not necessary to regularly
check power steering uid unless a
leak in the system is suspected
or an unusual noise is heard. A uid
loss in this system could indicate
a problem. Have the system
inspected and repaired.
How to Check Power
Steering Fluid
1. Turn the key off and let the
engine compartment cool down.
2. Wipe the cap and the top of the
reservoir clean.
3. Unscrew the cap and wipe the
dipstick with a clean rag.
4. Replace the cap and completely
tighten it.
5. Then remove the cap again and
look at the uid level on the
dipstick.
The level should be between the
ADD and FULL marks. If necessary,
add only enough uid to bring the
level up to the proper range.
What to Use
To determine what kind of uid to
use, seeRecommended Fluids and
Lubricants on page 6-12. Always
use the proper uid.
Notice:Use of the incorrect uid
may damage the vehicle and
the damages may not be covered
by the vehicle’s warranty.
Always use the correct uid
listed inRecommended Fluids
and Lubricants on page 6-12.
Service and Appearance Care 5-29