2007 HUMMER H3 engine

Use the following chart to determine how much your vehicle can weigh, based upon your vehicle model
and options.
Engine Axle Ratio Maximum Trailer Weight *GCWR
Automatic Transmission 4.56 4,500 lbs (2 041 kg) 9,500 lbs (4 309 kg)
Manual Transmission 4.56 3,000 lbs (1 364 kg) 8,000 lbs (3 629 kg)
*The Gross Combination Weight Rating (GCWR) in the total allowable weight of the completely loaded vehicle
and trailer including any passengers, cargo, equipment and conversions. The GCWR for your vehicle should
not be exceeded.
You can ask your dealer for our trailering
information or advice, or you can write us at
our Customer Assistance Offices. SeeCustomer
Assistance Offices on page 452for more
information.
Weight of the Trailer Tongue
The tongue load (A) of any trailer is an important
weight to measure because it affects the total
gross weight of your vehicle. The Gross Vehicle
Weight (GVW) includes the curb weight of
the vehicle, any cargo you may carry in it, and
the people who will be riding in the vehicle.If you have a lot of options, equipment, passengers
or cargo in your vehicle, it will reduce the tongue
weight your vehicle can carry, which will also
reduce the trailer weight your vehicle can tow.
If you will tow a trailer, you must add the tongue
load to the GVW because your vehicle will be
carrying that weight, too. SeeLoading Your
Vehicle on page 289for more information about
your vehicle’s maximum load capacity.
299

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’s important to check occasionally to
be sure the trailer bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gearbefore
you start down a long or steep downgrade. If you
don’t shift down, you might have to use your
brakes so much that they would get hot and no
longer work well.
If you have an automatic transmission, 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
under heavy loads and/or hilly conditions.If you have a manual transmission and you
are towing a trailer, it is better not to use the
highest gear.
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.
For manual transmissions, let the engine run
while parked, preferably on level ground, with the
transmission out of gear and the parking brake
applied, for a few minutes before turning the
engine off. If you do get the overheat warning,
seeEngine Overheating on page 338.
305

Parking on Hills
{CAUTION:
You really should not park your
vehicle, with a trailer attached, on a hill.
If something goes wrong, your rig could
start to move. People can be injured,
and both your vehicle and the trailer can
be damaged.
But if you ever have to park your rig on a hill,
here’s how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet for an automatic transmission,
or into gear for a manual transmission.
Turn your wheels into the curb if facing
downhill or into traffic if facing uphill.
2. Have someone place chocks under the trailer
wheels.3. When the wheel chocks are in place, release
the regular brakes until the chocks absorb
the load.
4. Reapply the regular brakes. Then apply your
parking brake and shift into PARK (P) for an
automatic transmission or into gear for a
manual transmission.
5. Release the regular brakes.
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.
306

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, 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.
Trailer Wiring Harness
Light-Duty Trailer Wiring Package
If your vehicle is not equipped with a trailer
towing package, the chassis harness will
contain the following blunt cut circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
White: Ground
Brown: Tail Lamps
If you want to add on a trailer tow, it should be
installed by your dealer or a qualied service
center. Also, seeAdd-On Electrical Equipment
on page 416for more information.
307

Service........................................................ 314
Accessories and Modications................... 314
California Proposition 65 Warning.............. 315
Doing Your Own Service Work.................. 315
Adding Equipment to the Outside
of Your Vehicle...................................... 316
Fuel............................................................. 316
Gasoline Octane........................................ 316
Gasoline Specications.............................. 316
California Fuel........................................... 316
Additives................................................... 317
Fuels in Foreign Countries........................ 318
Filling the Tank......................................... 318
Filling a Portable Fuel Container............... 320
Checking Things Under the Hood.............. 321
Hood Release........................................... 321
Engine Compartment Overview.................. 322
Engine Oil................................................. 323Engine Oil Life System.............................. 326
Engine Air Cleaner/Filter............................ 328
Automatic Transmission Fluid.................... 329
Manual Transmission Fluid........................ 332
Hydraulic Clutch........................................ 334
Engine Coolant.......................................... 335
Radiator Pressure Cap.............................. 338
Engine Overheating................................... 338
Cooling System......................................... 340
Engine Fan Noise..................................... 345
Power Steering Fluid ................................. 345
Windshield Washer Fluid........................... 346
Brakes...................................................... 347
Battery...................................................... 351
Jump Starting............................................ 352
Rear Axle.................................................... 357
Four-Wheel Drive........................................ 358
Front Axle................................................... 358
Section 5 Service and Appearance Care
311

Appearance Care........................................ 406
Cleaning the Inside of Your Vehicle.......... 406
Fabric/Carpet............................................. 407
Leather...................................................... 408
Instrument Panel, Vinyl, and Other
Plastic Surfaces..................................... 409
Care of Safety Belts.................................. 409
Weatherstrips............................................ 409
Washing Your Vehicle............................... 410
Cleaning Exterior Lamps/Lenses................ 410
Finish Care............................................... 410
Windshield, Backglass, and Wiper Blades.... 411
Aluminum or Chrome-Plated Wheels......... 412
Tires......................................................... 413
Sheet Metal Damage................................. 413
Finish Damage.......................................... 413Underbody Maintenance............................ 413
Chemical Paint Spotting............................ 414
Vehicle Care/Appearance Materials............ 414
Vehicle Identication.................................. 415
Vehicle Identication Number (VIN)........... 415
Service Parts Identication Label............... 416
Electrical System........................................ 416
Add-On Electrical Equipment..................... 416
Windshield Wiper Fuses............................ 417
Power Windows and Other Power
Options.................................................. 417
Fuses and Circuit Breakers....................... 417
Engine Compartment Fuse Block............... 418
Capacities and Specications.................... 422
Section 5 Service and Appearance Care
313

California Proposition 65 Warning
Most motor vehicles, including this one, contain
and/or emit chemicals known to the State of
California to cause cancer and birth defects or other
reproductive harm. Engine exhaust, many parts and
systems (including some inside the vehicle), many
uids, and some component wear by-products
contain and/or emit these chemicals.
Doing Your Own Service Work
{CAUTION:
You can be injured and your vehicle could
be damaged if you try to do service work
on a vehicle without knowing enough
about it.
Be sure you have sufficient knowledge,
experience, the proper replacement
parts, and tools before you attempt any
vehicle maintenance task.
CAUTION: (Continued)
CAUTION: (Continued)

Be sure to use the proper nuts, bolts,
and other fasteners. English and metric
fasteners can be easily confused. If you
use the wrong fasteners, parts can later
break or fall off. You could be hurt.
If you want to do some of your own service work,
you will want to use the proper service manual.
It tells you much more about how to service your
vehicle than this manual can. To order the
proper service manual, seeService Publications
Ordering Information on page 465.
Your vehicle has an airbag system. Before
attempting to do your own service work, see
Servicing Your Airbag-Equipped Vehicle
on page 80.
You should keep a record with all parts receipts
and list the mileage and the date of any service
work you perform. SeeMaintenance Record
on page 444.
315

Adding Equipment to the Outside
of Your Vehicle
Things you might add to the outside of your
vehicle can affect the airow around it. This may
cause wind noise and affect windshield washer
performance. Check with your dealer before
adding equipment to the outside of your vehicle.
Fuel
Use of the recommended fuel is an important part
of the proper maintenance of your vehicle. To
help keep your engine clean and maintain optimum
vehicle performance, GM recommends the use
of gasoline advertised as TOP TIER Detergent
Gasoline.
Gasoline Octane
Use regular unleaded gasoline with a posted
octane rating of 87 or higher. If the octane rating is
less than 87, you may notice an audible knocking
noise when you drive, commonly referred to as
spark knock. If this occurs, use a gasoline rated at
87 octane or higher as soon as possible.If you are using gasoline rated at 87 octane or
higher and you hear heavy knocking, your engine
needs service.
Gasoline Specications
At a minimum, gasoline should meet ASTM
specication D 4814 in the United States or
CAN/CGSB-3.5 in Canada. Some gasolines may
contain an octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl
(MMT). General Motors recommends against the
use of gasolines containing MMT. SeeAdditives
on page 317for additional information.
California Fuel
If your vehicle is certied to meet California
Emissions Standards, it is designed to operate on
fuels that meet California specications. See the
underhood emission control label. If this fuel is not
available in states adopting California emissions
standards, your vehicle will operate satisfactorily on
fuels meeting federal specications, but emission
control system performance may be affected.
316