2003 CHEVROLET TAHOE fuel

If yours was built with trailering options, as many are,
it's ready for heavier trailers. But trailering is different
than just driving your vehicle by itself. Trailering means
changes in handling, durability and fuel economy.
Successful, safe trailering takes correct equipment, and
it has to be used properly.
That's the reason for this part. In it are many time-tested,
important trailering tips and safety rules. Many of
these are important for your safety and that of your
passengers. So please read this section carefully before
you pull a trailer.
If You Do Decide To Pull A Trailer
If you do, here are some important points:
·There are many different laws, including speed limit
restrictions, having to do with trailering. Make sure
your rig will be legal, not only where you live
but also where you'll be driving. A good source for
this information can be state or provincial police.
·Consider using a sway control if your trailer will
weigh less than 5,000 lbs. (2 270 kg). You should
always use a sway control if your trailer will
weigh more than 5,000 lbs. (2 270 kg). You can ask
a hitch dealer about sway controls.
·Don't tow a trailer at all during the ®rst 500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
·Then, during the ®rst 500 miles (800 km) that you
tow a trailer, don't drive over 50 mph (80 km/h)
and don't make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
·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). See ªTow/Haul Modeº later in
this section.
Three important considerations have to do with weight:
·the weight of the trailer,
·the weight of the trailer tongue
·and the weight on your vehicle's tires.
4-66

Tow/Haul Mode
Tow/haul is a feature that assists when pulling a heavy
trailer or a large or heavy load. The purpose of the
tow/haul mode is to:
·Reduce the frequency and improve the predictability
of transmission shifts when pulling a heavy trailer or
a large or heavy load.
·Provide the same solid shift feel when pulling a
heavy trailer or a large or heavy load as when
the vehicle is unloaded.
·Improve control of vehicle speed while requiring
less throttle pedal activity when pulling a heavy
trailer or a large or heavy load.
Your vehicle may be equipped with a button at the end
of the shift lever which, when pressed, enables
tow/haul. Your vehicle may be equipped with
AutorideŸ
žwhich further improves your vehicle's ride
while towing. SeeAutorideŸ on page 4-64for more
information. When the button is pressed, a light on the
instrument panel will illuminate to indicate that
tow/haul has been selected. Tow/haul may be turned off
by pressing the button again, at which time the
indicator light on the instrument panel will turn off. The
vehicle will automatically turn off tow/haul every time
it is started.Tow/haul is designed to be most effective when the
vehicle and trailer combined weight is at least 75% of
the vehicle's Gross Combined Weight Rating (GCWR).
See Weight of the Trailer later in this section.
Tow/haul is most useful under the following driving
conditions:
·When pulling a heavy trailer or a large or heavy
load through rolling terrain.
·When pulling a heavy trailer or a large or heavy
load in stop and go traffic.
·When pulling a heavy trailer or a large or heavy
load in busy parking lots where improved low
speed control of the vehicle is desired.
Operating the vehicle in tow/haul when lightly loaded or
with no trailer at all will not cause damage. However,
there is no bene®t to the selection of tow/haul when the
vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission driving
characteristics and reduced fuel economy. Tow/haul
is recommended only when pulling a heavy trailer or a
large or heavy load.
4-67

Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside
of Your Vehicle...........................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-5
Gasoline Speci®cations....................................5-5
California Fuel...............................................5-6
Additives.......................................................5-6
Fuel E-85 (85% Ethanol).................................5-7
Fuels in Foreign Countries...............................5-8
Filling Your Tank............................................5-9
Filling a Portable Fuel Container.....................5-11
Checking Things Under
the Hood....................................................5-12
Hood Release..............................................5-12
Engine Compartment Overview.......................5-14
Engine Oil...................................................5-18
Engine Air Cleaner/Filter................................5-23
Automatic Transmission Fluid.........................5-26
Engine Coolant.............................................5-29
Coolant Surge Tank Pressure Cap..................5-32
Engine Overheating.......................................5-33Cooling System............................................5-36
Engine Fan Noise.........................................5-42
Power Steering Fluid.....................................5-43
Windshield Washer Fluid................................5-44
Brakes........................................................5-45
Battery........................................................5-48
Jump Starting...............................................5-49
All-Wheel Drive..............................................5-55
Rear Axle.......................................................5-56
Four-Wheel Drive............................................5-57
Front Axle......................................................5-58
Bulb Replacement..........................................5-59
Halogen Bulbs..............................................5-59
Headlamps..................................................5-60
Front Turn Signal, Sidemarker and Daytime
Running Lamps.........................................5-61
Side Identi®cation Marker Lamps.....................5-62
Roof Marker Lamps......................................5-62
Taillamps.....................................................5-64
Replacement Bulbs.......................................5-66
Windshield Wiper Blade Replacement..............5-66
Section 5 Service and Appearance Care
5-1

CAUTION: (Continued)
·
Be sure to use the proper nuts, bolts and
other fasteners. ªEnglishº and ªmetricº
fasteners can be easily confused. If you
use the wrong fasteners, parts can later
break or fall off. You could be hurt.
Adding Equipment to the Outside of
Your Vehicle
Things you might add to the outside of your vehicle can
affect the air¯ow 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
Gasoline
The 8th digit of your vehicle identi®cation number (VIN)
shows the code letter or number that identi®es your
engine. You will ®nd the VIN at the top left of the
instrument panel. See
Vehicle Identi®cation Number
(VIN) on page 5-107.
If your vehicle has the 5.3L V8 engine (VIN Code Z
only), you may use either regular unleaded gasoline or
ethanol fuel containing up to 85% ethanol (E-85);
also see
Fuel E-85 (85% Ethanol) on page 5-7.Inall
other engines, including the 5.3L V8 (VIN Code T), use
only regular unleaded gasoline.
5-4

Gasoline Octane
Use regular unleaded gasoline with a posted octane of 87
or higher. If the octane is less than 87, you may get a
heavy knocking noise when you drive. If this occurs, use
a gasoline rated at 87 octane or higher as soon as
possible. Otherwise, you might damage your engine.
A little pinging noise when you accelerate or drive uphill is
considered normal. This does not indicate a problem
exists or that a higher-octane fuel is necessary. If you are
using 87 octane or higher-octane fuel and hear heavy
knocking, your engine needs service.
Gasoline Speci®cations
It is recommended that gasoline meet speci®cations
which were developed by the American Automobile
Manufacturers Association and endorsed by the
Canadian Vehicle Manufacturers Association for better
vehicle performance and engine protection. Gasoline
meeting these speci®cations could provide improved
driveability and emission control system performance
compared to other gasoline.
In Canada, look for the
ªAuto Makers' Choiceº
label on the pump.
Canada Only
5-5

California Fuel
If your vehicle is certi®ed to meet California Emission
Standards (see the underhood emission control label), it
is designed to operate on fuels that meet California
speci®cations. If this fuel is not available in states
adopting California emissions standards, your vehicle will
operate satisfactorily on fuels meeting federal
speci®cations, but emission control system performance
may be affected. The malfunction indicator lamp may turn
on (see
Malfunction Indicator Lamp on page 3-47) and
your vehicle may fail a smog-check test. If this occurs,
return to your authorized GM dealer for diagnosis. If it is
determined that the condition is caused by the type of fuel
used, repairs may not be covered by your warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work properly.
You should not have to add anything to your fuel.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area to contribute to clean air. General Motors
recommends that you use these gasolines, particularly if
they comply with the speci®cations described earlier.
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage would not be covered under
your warranty.
5-6

Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors does
not recommend the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs and
the performance of the emission control system may
be affected. The malfunction indicator lamp may turn on.
If this occurs, return to your authorized GM dealer for
service.
Fuel E-85 (85% Ethanol)
The 8th digit of your vehicle identi®cation number (VIN)
shows the code letter or number that identi®es your
engine. You will ®nd the VIN at the top left of the
instrument panel. See
Vehicle Identi®cation Number
(VIN) on page 5-107.
If your vehicle has the 5.3L V8 engine (VIN Code Z
only), you may use either regular unleaded gasoline or
ethanol fuel containing up to 85% ethanol (E-85);
also see
Fuel on page 5-4. In all other engines, including
the 5.3L V8 (VIN Code T), use only regular unleaded
gasoline.Only vehicles that have the 5.3L V8 engine (VIN Code Z)
may use 85% ethanol fuel (E-85).
Many service stations will not have an 85% ethanol fuel
(E-85) pump available. The U. S. Department of
Energy has an alternative fuels website
(http://afdcmap.nrel.gov/nrel/) that can help you ®nd
E-85 fuel. Those stations that do have E-85 should have
a label indicating ethanol content. Do not use the fuel
if the ethanol content is
greaterthan 85%. Your vehicle
may not operate properly if the ethanol content is
greater than 85%.
At a minimum, E-85 should meet ASTM Speci®cation
D 5798.
To insure quick starts in the wintertime, the E-85 fuel
must be formulated properly for your climate according
to ASTM speci®cation D 5798. If you have trouble
starting on E-85, it may be because your E-85 fuel is
not properly formulated for your climate. If this happens,
switching to gasoline or adding gasoline to your fuel
tank may improve starting. Your vehicle is designed to
accommodate a mixture of gasoline and E-85 fuel.
For good starting and heater efficiency below 32ÉF
(0ÉC), the fuel mix in the fuel tank should contain no
more than 70% ethanol.
5-7

E-85 has less energy per gallon than gasoline, so you'll
need to re®ll your fuel tank more often when using
E-85 than when you're using gasoline. Regular unleaded
gasoline is recommended when pulling a trailer. For
payload capacity with ethanol fuel, see
Loading
Your Vehicle on page 4-62.
Notice:Some additives are not compatible with
E-85 fuel and may harm your fuel system. Damage
caused by additives wouldn't be covered by
your new vehicle warranty. Don't use additives with
E-85 fuel.
Notice:Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage would not be covered under
your warranty.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard
to ®nd. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel would not
be covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you will be driving.
5-8