2004 CHEVROLET SILVERADO fuel

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 the 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 benet 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.
Weight of the Trailer
How heavy can a trailer safely be?
It depends on how you plan to use your rig. For
example, speed, altitude, road grades, outside
temperature and how much your vehicle is used to pull
a trailer are all important. And, it can also depend
on any special equipment that you have on your vehicle.
Use one of the following charts to determine how
much your vehicle can weigh, based upon your vehicle
model and options.
Maximum trailer weight is calculated assuming the
driver and one passenger are in the tow vehicle and it
has all the required trailering equipment. The weight
of additional optional equipment, passengers and cargo
in the tow vehicle must be subtracted from the
maximum trailer weight.
Above the 5,000 lbs. (2 268 kg) trailer rating, the
handling/trailering suspension is required on
C-1500 models and the handling/trailering or off-road
suspension is required on K-1500 models.
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Service............................................................5-3
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-7
Fuel E-85 (85% Ethanol).................................5-8
Fuels in Foreign Countries...............................5-9
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...................................................5-20
Engine Air Cleaner/Filter................................5-25
Automatic Transmission Fluid
(Except Allison Transmission
®) ....................5-27
Automatic Transmission Fluid
(Allison Transmission
®) ...............................5-30
Manual Transmission Fluid.............................5-33
Hydraulic Clutch...........................................5-34Engine Coolant.............................................5-35
Coolant Surge Tank Pressure Cap..................5-38
Engine Overheating.......................................5-38
Cooling System............................................5-41
Engine Fan Noise.........................................5-46
Power Steering Fluid.....................................5-46
Windshield Washer Fluid................................5-47
Brakes........................................................5-49
Battery........................................................5-52
Jump Starting...............................................5-53
All-Wheel Drive..............................................5-58
Rear Axle.......................................................5-59
Four-Wheel Drive............................................5-60
Noise Control System.....................................5-61
Tampering with Noise Control System
Prohibited.................................................5-61
Bulb Replacement..........................................5-63
Halogen Bulbs..............................................5-63
Headlamps..................................................5-63
Front Turn Signal, Sidemarker and
Daytime Running Lamps.............................5-65
Roof Marker Lamps......................................5-66
Center High-Mounted Stoplamp (CHMSL)
and Cargo Lamp.......................................5-68
Section 5 Service and Appearance Care
5-1

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
If your vehicle has a diesel engine, see “Diesel
Fuel Requirements and Fuel System” in the Diesel
Engine Supplement.
For vehicles with gasoline engines, please read this.
Gasoline Octane
For all except the Silverado SS model, 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.
If you have the Silverado SS model, use premium
unleaded gasoline with a posted octane of 91 or higher
for best performance. You may also use middle
grade or regular unleaded gasoline rated at 87 octane
or higher, but your vehicle’s acceleration may be slightly
reduced. If the octane is less than 87, you may get a
heavy knocking noise when you drive. If this occurs, use
gasoline rated at 87 octane or higher as soon as
possible. Otherwise, you might damage your engine.
5-5

Gasoline Specications
It is recommended that gasoline meet specications
which were developed by automobile manufacturers
around the world and contained in the World-Wide
Fuel Charter which is available from the Alliance of
Automobile Manufacturers at www.autoalliance.org/
fuel_charter.htm. Gasoline meeting these specications
could provide improved driveability and emission control
system performance compared to other gasoline.
In Canada, look for the
“Auto Makers’ Choice”
label on the pump.
California Fuel
If your vehicle is certied to meet California Emission
Standards (see the underhood emission control label),
it is designed to operate on fuels that meet California
specications. 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. The malfunction indicator lamp may
turn on (seeMalfunction Indicator Lamp on page 3-48)
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.
Canada Only
5-6

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. However, some gasolines contain only the
minimum amount of additive required to meet U.S.
Environmental Protection Agency regulations. General
Motors recommends that you buy gasolines that
are advertised to help keep fuel injectors and intake
valves clean. If your vehicle experiences problems due
to dirty injectors or valves, try a different brand
of gasoline.
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 specications 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.
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.
5-7

Fuel E-85 (85% Ethanol)
The 8th digit of your vehicle identication number (VIN)
shows the code letter or number that identies your
engine. You will nd the VIN at the top left of the
instrument panel. SeeVehicle Identication Number
(VIN) on page 5-122.
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 seeFuel
on page 5-5. 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). General Motors
encourages the use of E-85 in vehicles that are designed
to use it. The ethanol in E-85 is a “renewable” fuel,
meaning it is made from renewable sources such as corn
and other crops.
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://www.afdc.doe.gov/refueling_mapsite.shtml) 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 isgreaterthan 85%.
Your vehicle may not operate properly if the ethanol
content is greater than 85%.
At a minimum, E-85 should meet ASTM
Specication D 5798.To insure quick starts in the wintertime, the E-85 fuel
must be formulated properly for your climate according
to ASTM specication 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 32°F
(0°C), the fuel mix in the fuel tank should contain no
more than 70% ethanol.
E-85 has less energy per gallon than gasoline, so you
will need to rell your fuel tank more often when
using E-85 than when you are using gasoline. Regular
unleaded gasoline is recommended when pulling a
trailer. For payload capacity with ethanol fuel, see
Loading Your Vehicle on page 4-56.
Notice:Some additives are not compatible with
E-85 fuel and may harm your fuel system. Damage
caused by additives would not be covered by
your new vehicle warranty. Do not 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.
5-8

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.
Filling Your Tank
{CAUTION:
Fuel vapor burns violently and a fuel re can
cause bad injuries. To help avoid injuries to
you and others, read and follow all the
instructions on the pump island. Turn off your
engine when you are refueling. Do not smoke
if you are near fuel or refueling your vehicle.
Keep sparks, ames and smoking materials
away from fuel. Do not leave the fuel pump
unattended when refueling your vehicle — this
is against the law in some places. Keep
children away from the fuel pump; never let
children pump fuel.
The fuel cap is located behind a hinged door on the
driver’s side of the vehicle.
To remove the fuel cap, turn it slowly to the left
(counterclockwise). It will require more effort to turn the
fuel cap on the last turn as you loosen it.
5-9

Before refueling, slide the edge of the fuel cap onto the
ller door hook.The cap will hang on the hook during refueling.
{CAUTION:
If a re starts while you are refueling, do not
remove the nozzle. Shut off the ow of fuel by
shutting off the pump or by notifying the
station attendant. Leave the area immediately.
If your vehicle is a dual fuel tank chassis cab model,
and it runs out of fuel, refuel the front fuel tank rst
to ensure a quick restart.
5-10