2010 HUMMER H3 engine

10-16 Vehicle Care
4. If the fluid level is good, installthe plug and be sure it is fully
seated. If the fluid level is low,
add more fluid as described in
the next steps.
How to Add Fluid
Refer to the Maintenance Schedule
to determine what kind of fluid to
use. See Recommended Fluids and
Lubricants on page 11‑8.
1. Remove the filler plug.
2. Add fluid at the filler plug hole. Add only enough fluid to bring
the fluid level up to the bottom of
the filler plug hole.
3. Install the filler plug. Be sure the plug is fully seated.
Hydraulic Clutch
The hydraulic clutch linkage in the
vehicle is self-adjusting. The clutch
master cylinder reservoir is filled
with hydraulic clutch fluid.
The hydraulic clutch fluid reservoir
cap has this symbol on it. See
Engine Compartment Overview
on
page 10‑6for reservoir location.
It is not necessary to regularly
check clutch fluid unless a leak in
the system is suspected. Adding
fluid will not correct a leak.
A fluid loss in this system could
indicate a problem. Have the
system inspected and repaired.
When to Check and What
to Use
Refer to the Maintenance Schedule
to determine how often to check
the fluid level in the clutch master
cylinder reservoir and for the proper
fluid. See Recommended Fluids and
Lubricants on page 11‑8.
How to Check and Add Fluid
The proper fluid 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.

Vehicle Care 10-17
Engine Air Cleaner/Filter
3.7 L shown (5.3 L similar)
The engine air cleaner/filter is
located in the engine compartment
on the passenger side of the
vehicle. See Engine Compartment
Overview
on page 10‑6for more
information on location.
When to Inspect the Engine Air
Cleaner/Filter
Inspect the air cleaner/filter at the
Maintenance IIintervals and replace
it at the first oil change after each
80 000 km (50,000 mile) interval.
See Scheduled Maintenance
on
page 11‑2for more information.
If you are driving in dusty/dirty
conditions, inspect the filter at each
engine oil change.
How to Inspect the Engine Air
Cleaner/Filter
To inspect or replace the engine air
cleaner/filter:
1. Unfasten the clips that hold the cover on and remove the cover.
2. Lift out the engine air cleaner/filter. 3. Inspect or replace the air filter.
See Maintenance Replacement
Parts
on page 11‑10to determine
which filter to use.
4. Reinstall the engine air cleaner/filter cover. Fasten the
clips to hold the cover in place.
{WARNING
Operating the engine with the air
cleaner/filter off can cause you
or others to be burned. The air
cleaner not only cleans the air; it
helps to stop flames if the engine
backfires. Use caution when
working on the engine and do not
drive with the air cleaner/filter off.
Notice: If the air cleaner/filter is
off, dirt can easily get into the
engine, which could damage it.
Always have the air cleaner/filter
in place when you are driving.

10-18 Vehicle Care
Cooling System
The cooling system allows the
engine to maintain the correct
working temperature.
3.7L L5 Engine
A. Coolant Recovery Tank
B. Engine Cooling Fan
C. Radiator Pressure Cap
5.3L V8 Engine
A. Coolant Recovery Tank
B. Radiator Pressure Cap
C. Engine Cooling Fan
{WARNING
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.
{WARNING
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 fire, and you
could be burned. Get any leak
fixed 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 50 000 km
(30,000 miles) or 24 months,
whichever occurs first. Any
repairs would not be covered by
the vehicle warranty. Always use
DEX-COOL
®(silicate-free) coolant
in the vehicle.

Vehicle Care 10-19
Engine Coolant
The cooling system in the vehicle
is filled with DEX-COOL®engine
coolant. This coolant is designed to
remain in the vehicle for five years
or 240 000 km (150,000 miles),
whichever occurs first.
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,
see Engine Overheating
on
page 10‑22.
What to Use
{WARNING
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.
(Continued)
WARNING (Continued)
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 fire 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 −37°C (−34°F), outside
temperature.
.Gives boiling protection up
to 129°C (265°F), 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.
See Recommended Fluids and
Lubricants
on page 11‑8for more
information.

10-20 Vehicle Care
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. See
Engine Compartment Overview
on
page 10‑6for 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 anything
else 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
{WARNING
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
specific coolant fill 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.
How to Add Coolant to the
Radiator
{WARNING
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.

Vehicle Care 10-21
{WARNING
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 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. 3. Fill the radiator with the proper
DEX‐COOL coolant mixture,
up to the base of the filler
neck. See Engine Coolant
on
page 10‑19for 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.

10-22 Vehicle Care
6. Start the engine and let it rununtil 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 filler neck
might be lower. If the level is
lower, add more of the proper
DEX‐COOL coolant mixture
through the filler neck until the
level reaches the base of the
filler neck.
8. Then replace the pressure cap. At any time during this procedure
if coolant begins to flow out of
the filler 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.
Engine Overheating
The vehicle has an indicator to warn
of engine overheating.
A coolant temperature gauge is
displayed on the instrument panel.
See Engine Coolant Temperature
Gauge on page 5‑9.
You may decide not to lift the
hood when this warning appears,
but instead get service help right
away. See Roadside Service
on
page 13‑5.
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
fire because of being driven
with no coolant, your vehicle can
be badly damaged. The costly
repairs would not be covered by
the vehicle warranty.

Vehicle Care 10-23
If Steam Is Coming From The
Engine Compartment
{WARNING
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 fire. You or others
could be badly burned. Stop your
engine if it overheats, and get out
of the vehicle until the engine
is cool.
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” underTrailer Towingon
page 9‑74.
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 gauge
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.