2008 HUMMER H2 overheating

Ashtray(s) and Cigarette Lighter
If your vehicle has an ashtray, it is removable and ts
into the front cupholder. Pull up on the ashtray door
to open it.
Notice:If you put papers, pins, or other ammable
items in the ashtray, hot cigarettes or other
smoking materials could ignite them and possibly
damage your vehicle. Never put ammable items
in the ashtray.
To remove the ashtray, pull it out from the console.
To reinstall the ashtray, slide it back to the original
position.
To use the cigarette lighter, if equipped, push it in all
the way, and let go. When it’s ready, it will pop back
out by itself.
Notice:Holding a cigarette lighter in while it is
heating does not let the lighter back away from
the heating element when it is hot. Damage from
overheating can occur to the lighter or heating
element, or a fuse could be blown. Do not hold
a cigarette lighter in while it is heating.
Analog Clock
The analog clock is located on the instrument
panel above the radio. The clock is not connected
with any other vehicle system and runs by itself.
To adjust the clock:
1. Locate the adjustment button directly below the
clock face.
2. Push and hold the adjustment button to advance
the clock hands. Holding the button down will
cause the clock to advance faster. Release the
button before reaching the desired time.
3. Push and release the button to increase the time
by one minute increments until the desired time
is reached.
3-21

StabiliTrak®Indicator Light
If equipped, this
warning light should
come on briey when
the engine is started.
If the warning light does not come on then, have it xed
so it will be ready to warn you if there is a problem.
If it stays on, or comes on when you are driving,
there may be a problem with your StabiliTrak
®system
and your vehicle may need service. When this warning
light is on, the system is off and will not limit wheel
spin. Adjust your driving accordingly.
This light will also ash when the StabiliTrak
®system
is active.
If the StabiliTrak
®system warning light comes on
and stays on for an extended period of time when
the system is turned on, your vehicle needs service.
SeeStabiliTrak
®System on page 4-7for more
information.
Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
It also provides an indicator of how hard your vehicle
is working. During a majority of the operation, the gage
will read 210°F (100°C) or less. If you are pulling a
load or going up hills, it is normal for the temperature
to uctuate and approach the 250°F (122°C) mark.
If the gage reaches the 260°F (125°C) mark, it indicates
that the cooling system is working beyond its capacity.
SeeEngine Overheating on page 5-27.
United StatesCanada
3-40

DRIVER DOOR OPEN
This message displays and a chime sounds if the
driver door is not fully closed and the vehicle is in a
drive gear. Stop and turn off the vehicle, check the
door for obstructions, and close the door again.
Check to see if the message still appears on the DIC.
ENGINE HOT A/C (Air Conditioning)
TURNED OFF
This message displays when the engine coolant
becomes hotter than the normal operating temperature.
SeeEngine Coolant Temperature Gage on page 3-40.
To avoid added strain on a hot engine, the air
conditioning compressor automatically turns off.
When the coolant temperature returns to normal,
the air conditioning compressor turns back on.
You can continue to drive your vehicle.
If this message continues to appear, have the
system repaired by your dealer/retailer as soon
as possible to avoid damage to the engine.
ENGINE OVERHEATED IDLE ENGINE
Notice:If you drive your vehicle while the engine
is overheating, severe engine damage may occur.
If an overheat warning appears on the instrument
panel cluster and/or DIC, stop the vehicle as soon
as possible. SeeEngine Overheating on page 5-27
for more information.
This message displays when the engine coolant
temperature is too hot. Stop and allow the vehicle to
idle until it cools down. SeeEngine Coolant
Temperature Gage on page 3-40.
SeeOverheated Engine Protection Operating Mode
on page 5-28for information on driving to a safe place
in an emergency.
ENGINE POWER IS REDUCED
This message displays and a chime sounds when
the cooling system temperature gets too hot and the
engine further enters the engine coolant protection
mode. SeeEngine Overheating on page 5-27for
further information.
3-57

TIGHTEN GAS CAP
This message may display along with the check engine
light on the instrument panel cluster if the vehicle’s
fuel cap is not tightened properly. SeeMalfunction
Indicator Lamp on page 3-42. Reinstall the fuel cap
fully. SeeFilling the Tank on page 5-7. The diagnostic
system can determine if the fuel cap has been left off
or improperly installed. A loose or missing fuel cap
allows fuel to evaporate into the atmosphere.
A few driving trips with the cap properly installed
should turn this light and message off.
TIRE LEARNING ACTIVE
This message displays when the Tire Pressure Monitor
System (TPMS) is re-learning the tire positions on your
vehicle. The tire positions must be re-learned after
rotating the tires or after replacing a tire or sensor. See
Tire Inspection and Rotation on page 5-67,Tire Pressure
Monitor System on page 5-62, andInflation - Tire
Pressure on page 5-61for more information.
TRACTION CONTROL OFF
This message displays when you turn off the Traction
Control System (TCS) or when the TCS has been
automatically disabled. Adjust your driving accordingly.
SeeTraction Control System (TCS) on page 4-5and
StabiliTrak
®System on page 4-7for more information.
TCS may be automatically disabled due to overheating,
which could occur if the TCS activates continuously
for an extended period of time.
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.
3-62

Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you are turning with a trailer, make wider turns
than normal. Do this so your trailer will not strike
soft shoulders, curbs, road signs, trees or other objects.
Avoid jerky or sudden maneuvers. Signal well in
advance.
Turn Signals When Towing a Trailer
The arrows on your instrument panel will ash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also ash, telling other drivers
you’re about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will ash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It is
important to check occasionally to be sure the trailer
bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you do not 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.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. 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 5-27.
4-64

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-3
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-4
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-6
Filling the Tank..............................................5-7
Filling a Portable Fuel Container.......................5-9
Checking Things Under the Hood.....................5-9
Hood Release..............................................5-10
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-13
Engine Oil Life System..................................5-16
Engine Air Cleaner/Filter................................5-18
Automatic Transmission Fluid.........................5-21
Engine Coolant.............................................5-24
Coolant Surge Tank Pressure Cap..................5-26
Engine Overheating.......................................5-27Overheated Engine Protection
Operating Mode.........................................5-28
Cooling System............................................5-29
Engine Fan Noise.........................................5-33
Power Steering Fluid.....................................5-34
Windshield Washer Fluid................................5-35
Brakes........................................................5-36
Battery........................................................5-39
Jump Starting...............................................5-40
Rear Axle.......................................................5-45
Four-Wheel Drive............................................5-46
Front Axle......................................................5-47
Bulb Replacement..........................................5-48
Halogen Bulbs..............................................5-48
Headlamps..................................................5-48
Front Turn Signal and Parking Lamps..............5-49
Daytime Running Lamps (DRL).......................5-50
Roof Marker Lamps......................................5-50
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps.........................................5-51
Replacement Bulbs.......................................5-53
Windshield Wiper Blade Replacement..............5-54
Tires..............................................................5-55
Tire Sidewall Labeling...................................5-56
Tire Terminology and Denitions.....................5-58
Section 5 Service and Appearance Care
5-1

Automatic Transmission Fluid
When to Check and Change Automatic
Transmission Fluid
It is usually not necessary to check the transmission
uid level. The only reason for uid loss is a
transmission leak or overheating the transmission. If you
suspect a small leak, then use the following checking
procedures to check the uid level. However, if there is
a large leak, then it may be necessary to have the
vehicle towed to a dealer/retailer service department and
have it repaired before driving the vehicle further.
Notice:Use of the incorrect automatic transmission
uid may damage your vehicle, and the damages
may not be covered by your warranty. Always
use the automatic transmission uid listed in
Recommended Fluids and Lubricants on page 6-12.
Change the uid and lter at the intervals listed in the
Maintenance Schedule. SeeScheduled Maintenance on
page 6-4. Be sure to use the transmission uid listed in
Recommended Fluids and Lubricants on page 6-12.
How to Check Automatic
Transmission Fluid
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.
Before checking the uid level, prepare your vehicle
as follows:
1. Start the engine and park your vehicle on a level
surface. Keep the engine running.
2. Apply the parking brake and place the shift lever
in PARK (P).
3. With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, move the
shift lever back to PARK (P).
4. Allow the engine to idle (500 – 800 rpm) for at least
one minute. Slowly release the brake pedal.
5. Keep the engine running and press the Trip/Fuel
button or trip odometer reset stem until TRANS
TEMP (Transmission Temperature) displays on the
Driver Information Center (DIC).
5-21

Consistency of Readings
Always check the uid level at least twice using the
procedures described. Consistency (repeatable
readings) is important to maintaining proper uid level.
If uid is added, it may take 15 minutes or longer to
obtain an accurate reading because of residual
uid draining down the dipstick tube. If inconsistent
readings persist, check the transmission breather to be
sure it is clean and not clogged. If readings are still
inconsistent, contact your dealer/retailer.
Engine Coolant
The cooling system in your vehicle is lled with
DEX-COOL®engine coolant. This coolant is designed
to remain in your vehicle for ve years or 150,000 miles
(240 000 km), whichever occurs rst, if you add only
DEX-COOL
®extended life coolant.
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 5-27.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.
5-24