cooling HUMMER H2 2007 User Guide

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal
down while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the
chocks.
4. Stop and have someone pick up and store
the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when
you’re pulling a trailer. See the Maintenance
Schedule for more on this. Things that are
especially important in trailer operation are
automatic transmission uid (don’t overll),
engine oil, axle lubricant, belts, cooling system
and brake system. Each of these is covered in
this manual, and the Index will help you nd them
quickly. If you’re trailering, it’s a good idea to
review these sections before you start your trip.
Check periodically to see that all hitch nuts
and bolts are tight.
385

Service........................................................ 392
Accessories and Modications................... 392
California Proposition 65 Warning.............. 393
Doing Your Own Service Work.................. 393
Adding Equipment to the Outside of
Your Vehicle.......................................... 394
Fuel............................................................. 394
Gasoline Octane........................................ 394
Gasoline Specications.............................. 394
California Fuel........................................... 395
Additives................................................... 395
Fuels in Foreign Countries........................ 396
Filling the Tank......................................... 397
Filling a Portable Fuel Container............... 399
Checking Things Under the Hood.............. 400
Hood Release........................................... 400
Engine Compartment Overview.................. 402
Engine Oil................................................. 404
Engine Oil Life System.............................. 407
Engine Air Cleaner/Filter............................ 409
Automatic Transmission Fluid.................... 412
Engine Coolant.......................................... 415Coolant Surge Tank Pressure Cap............ 418
Engine Overheating................................... 418
Overheated Engine Protection
Operating Mode..................................... 420
Cooling System......................................... 420
Power Steering Fluid ................................. 425
Windshield Washer Fluid........................... 426
Brakes...................................................... 427
Battery...................................................... 431
Jump Starting............................................ 432
Rear Axle.................................................... 437
Four-Wheel Drive........................................ 438
Front Axle................................................... 440
Bulb Replacement....................................... 441
Halogen Bulbs........................................... 441
Headlamps................................................ 441
Front Turn Signal and Parking Lamps.......... 442
Daytime Running Lamps (DRL)................. 443
Roof Marker Lamps................................... 443
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps...................................... 444
Replacement Bulbs................................... 446
Section 5 Service and Appearance Care
389

A. Coolant Surge Tank. SeeCooling System on
page 420andCoolant Surge Tank Pressure
Cap on page 418.
B. Engine Air Cleaner/Filter and Air Filter
Restriction Indicator (If Equipped). SeeEngine
Air Cleaner/Filter on page 409.
C. Windshield Washer Fluid Reservoir. See
“Adding Washer Fluid” underWindshield
Washer Fluid on page 426.
D. Engine Oil Fill Cap. See “When to Add Engine
Oil” underEngine Oil on page 404.
E. Engine Oil Dipstick. See “Checking Engine Oil”
underEngine Oil on page 404.
F. Automatic Transmission Fluid Dipstick.
See “Checking the Fluid Level” underAutomatic
Transmission Fluid on page 412.G. Engine Cooling Fan. SeeCooling System on
page 420.
H. Remote Negative (−) Terminal (GND).
SeeJump Starting on page 432.
I. Power Steering Fluid Reservoir (Out of View).
SeePower Steering Fluid on page 425.
J. Remote Positive (+) Terminal. SeeJump
Starting on page 432.
K. Brake Fluid Reservoir. See “Brake Fluid” under
Brakes on page 427.
L. Underhood Fuse Block. SeeUnderhood Fuse
Block on page 507.
M. Battery. SeeBattery on page 431.
403

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 inRecommended
Fluids and Lubricants on page 528.
After adding uid, recheck the uid level as
described under “How to Check Automatic
Transmission Fluid,” earlier in this section.
When the correct uid level is obtained, push
the dipstick back in all the way; then ip the
handle down to lock the dipstick in place.
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 418.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.
415

What Kind of Coolant to Use
Use a mixture of one-half clean, drinkable water
and one-half DEX-COOL®coolant which will
not damage aluminum parts. If you use this coolant
mixture, you do not need to add anything else.
{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 DEX-COOL
®coolant.Notice:If you use an improper coolant
mixture, your engine could overheat and be
badly damaged. The repair cost would not be
covered by your warranty. Too much water
in the mixture can freeze and crack the engine,
radiator, heater core, and other parts.
If you have to add coolant more than four times a
year, have your dealer check your cooling
system.
Notice:If you use extra inhibitors and/or
additives in your vehicle’s cooling system, you
could damage your vehicle. Use only the
proper mixture of the engine coolant listed in
this manual for the cooling system. See
Recommended Fluids and Lubricants on
page 528for more information.
416

Overheated Engine Protection
Operating Mode
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 on page 404.
Cooling System
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
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.
420

Check the coolant level after the system cools
down. Some amount of coolant may be lost due to
overheating.
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.If there seems to be no leak, start the engine
again. The engine cooling fan speed should
increase when idle speed is doubled by pushing
the accelerator pedal down. If it does not,
your vehicle needs service. Turn off the engine.
Notice:Engine damage from running your
engine without coolant is not covered by your
warranty. SeeOverheated Engine Protection
Operating Mode on page 420for information on
driving to a safe place in an emergency.
Notice:Using coolant other than DEX-COOL
®
may 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 your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your
vehicle.
421

How to Add Coolant to the Coolant
Surge Tank
If you have not found a problem yet, check to see
if coolant is visible in the surge tank. 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 surge tank, but be sure the
cooling system, including the coolant surge tank
pressure cap, is cool before you do it. SeeEngine
Coolant on page 415for more information.
If no coolant is visible in the surge tank, add
coolant as follows:
{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.
CAUTION: (Continued)
CAUTION: (Continued)
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.
{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 DEX-COOL
®coolant.
422

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. Locate the coolant
surge tank pressure
cap that has this
label.2. You can remove the coolant surge tank
pressure cap when the cooling system,
including the coolant surge tank pressure cap
and upper radiator hose, are 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.
3. Then keep turning the pressure cap slowly,
and remove it.
423

4. Fill the coolant surge tank with the proper
mixture, to the FULL COLD mark.5. With the coolant surge tank pressure cap off,
start the engine and let it run until you can
feel the upper radiator hose getting hot.
Watch out for the engine cooling fan.
By this time, the coolant level inside the
coolant surge tank may be lower. If the level
is lower, add more of the proper mixture
to the coolant surge tank until the level
reaches the FULL COLD mark.
6. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
424