Fuel
If your vehicle has a diesel engine, seeDiesel Engine
Fuel on page 5-8.
For vehicles with gasoline engines, please read this.
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 specifications
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.
Gasoline meeting these specifications 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.
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 specifications 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
Diesel Engine Fuel
For the Caterpillar®diesel, see the Caterpillar®
Operation & Maintenance Manual for information
concerning fuel usage.
Notice:Diesel fuel or fuel additives not
recommended in this manual could damage your
fuel system and engine. Your warranty would
not cover this damage. And:
Diesel fuel that has been mixed with engine oil
or automatic transmission uid could damage
your engine and emission controls.
Aftermarket diesel fuel additives are not tested
by General Motors. Some additives, particularly
those which contain alcohol or water
emulsi ers, may damage your fuel system. If
you believe that unique circumstances call for a
fuel additive to be used, consult your dealer
for advice.
If you ever run out of diesel fuel, it can be
difficult to restart your engine. To avoid all this,
never let your tank get empty.
If you run out of fuel,Running Out of Fuel on page 5-15,
tells you how to restart your engine.
What Fuel to Use
In the United States, for best results use Number 2–D
diesel fuel year-round (above and below freezing
conditions) as oil companies blend Number 2–D fuel to
address climate differences. Number 1–D diesel fuel
may be used in very cold temperatures (when it
stays below 0°F or−18°C); however, it will produce a
power and fuel economy loss. Avoid the use of Number
1–D diesel fuel in warm or hot climates. It may result
in stalling, poor starting when the engine is hot and may
damage the fuel injection system.
At a minimum, the diesel fuel you use should meet
specifications ASTM D975-02 (Grade Low Sulfur) in the
United States. In addition, the Engine Manufacturers
Association (EMA) has identified properties of an
improved diesel fuel for better engine performance and
durability. Diesel fuels corresponding to the EMA
Recommended Guideline on Premium Diesel Fuel
(FQP-1A) could provide better starting, less noise and
better vehicle performance. If there are questions
about the fuel you are using, contact your fuel supplier.
It is acceptable to use diesel fuel containing up to
5% biodiesel (B5), but the final blended fuel must meet
the same specification, ASTM D975–02 (Grade Low
Sulfur), as other fuels used in your vehicle, and
the biodiesel used for making this fuel must meet the
ASTM D6751–02 specification.
5-8
Biodiesel is produced from vegetable oils or animal fat
that have been chemically modified to reduce the
possibility of damage to your fuel system and engine.
Higher concentration (i.e., greater than B5)
biodiesel-containing fuels or the use of unmodified
bio-oils blended into diesel fuel at any concentration is
not recommended and could damage your fuel
system and engine. Such damage would not be covered
by your warranty. If there are questions about the
biodiesel-containing fuels you are using, contact your
fuel supplier.
Diesel fuel may foam when you fill your tank. This can
cause the automatic pump nozzle to shut off, even
though your tank is not full. If this happens, just wait for
the foaming to stop and then continue to fill your tank.
{CAUTION:
Heat coming from the engine may cause the
fuel to expand and force the fuel out of your
tank. If something ignites the fuel, a re could
start and people could be burned. To help avoid
this, ll your fuel tank only until the automatic
nozzle shuts off. Do not try to “top it off.”
What Fuel to Use in Canada
Canadian fuels are blended for seasonal changes.
Diesel Type “A” fuel is blended for better cold weather
starting (below 0°F or−18°C); however, you may
notice some power and fuel economy loss. If Type “A”
fuel is used in warmer temperatures, stalling and
hard starting may occur. Diesel Type “B” fuel is blended
for temperatures above 0°F (−18°C). The emission
control system requires the use of diesel fuel with
low-sulfur (.05% by weight) content. Both low- and
higher-sulfur fuels will be available in Canada. Only
low-sulfur diesel fuels are available in the United States.
It is important that diesel-powered trucks are refueled
only with low-sulfur fuel. Use of fuels with higher-sulfur
content will affect the function of the emission
components and may cause reduced performance,
excessive smoke and unpleasant odor.
At a minimum, the diesel fuel you use should meet
specifications CAN/CGSB–3.517–2000 (Low Sulfur
Diesel) in Canada. In addition, the Engine Manufacturers
Association (EMA) has identified properties of an
improved diesel fuel for better engine performance and
durability (FQP-1A). Diesel fuels corresponding to
the EMA description could provide better starting, less
noise and better vehicle performance. If there are
questions about the fuel you are using, contact your fuel
supplier.
5-9
It is acceptable to use diesel fuel containing up to 5%
biodiesel (B5), but the final blended fuel must meet
the same specification, CAN/CGSB—3.517–2000 (Low
Sulfur Diesel) in Canada, as other fuels used in your
vehicle, and the biodiesel used for making this fuel must
meet the ASTM D6751–02 specification. Biodiesel is
produced from vegetable oils or animal fat that
have been chemically modified to reduce the possibility
of damage to your fuel system and engine. Higher
concentration (i.e., greater than B5) biodiesel-containing
fuels or the use of unmodified bio-oils blended into
diesel fuel at any concentration is not recommended and
could damage your fuel system and engine. Such
damage would not be covered by your warranty. If there
are questions about the biodiesel-containing fuels you
are using, contact your fuel supplier.
Very Cold Weather Operation
Follow the instructions listed previously under the
heading “What Fuel to Use.”
Notice:Never use home heating oil or gasoline in
your diesel engine. They can cause engine
damage.
In cold weather, your fuel filter may become clogged
(waxed). To unclog it, move the vehicle to a warm
garage area and warm the filter to between 32°F and
50°F (0°C to 10°C). You will not need to replace it.
Additional information on the fuel filter follows.
Water in Fuel
{CAUTION:
Diesel fuel containing water is still ammable.
You could be burned. If you ever try to drain
water from your fuel, keep sparks, ames and
smoking materials away from the mixture.
Notice:If there is water in your diesel fuel and the
weather is warm or humid, fungus and bacteria
can grow in the fuel. They can damage your
fuel system. A diesel fuel biocide can be used to
sterilize your fuel system. However, your fuel system
may still need to be cleaned. Your dealer can
advise you of the appropriate solution.
If your fuel tank needs to be purged to remove
water, see your dealer or a quali ed technician.
Improper purging can damage your fuel system.
5-10
Sometimes, water can be pumped into your fuel tank
along with your diesel fuel. This can happen if a service
station doesn’t regularly inspect and clean its fuel
tanks, or if it gets contaminated fuel from its suppliers.
If this happens, a
water-in-fuel light will come
on. If it does, the water
must be drained. Your
dealer can show you how
to do this.
If it comes on, use the following chart.
Water In Fuel Light Chart
Problem Recommended Action
Light comes on
intermittently.Drain water from fuel
filter.
Light stays on at
temperatures above
freezing.Drain fuel filter
immediately. If no water
can be drained and light
stays on, see your dealer
for assistance.
Water In Fuel Light Chart (cont’d)
Problem Recommended Action
Light stays on at
temperatures below
freezing.Drain fuel filter
immediately. If no water
can be drained — water
may be frozen in water
drain system. Water may
be frozen in the fuel lines.
Move the vehicle to a
warm location to thaw
out, and then drain filter
system.
Light stays on
immediately after
refueling, large amount of
water possibly pumped
into fuel tank.Fuel tank purging
required. See your dealer
for assistance.
Notice:If you drive when this warning indicator is
on, you can damage your fuel injection system
and your engine. If the indicator comes on right after
you refuel, it means water was pumped into your
fuel tank. Turn off your engine immediately.
Then, have the water drained at once.
5-11
To drain water, do the following:
1. Stop and park the vehicle in a safe place. Turn off
the engine and apply the parking brake.
2. Remove the fuel cap.
3. Place a fuel-resistant container under the fuel filter.
The filter drain valve is located on the bottom of the
fuel filter. The fuel filter is located in the engine
compartment on the passenger’s side of the vehicle,
or on the driver’s side frame rail near the engine.
4. Open the drain valve
by turning two to three
turns. When fuel
empties from the valve,
all the water has
been drained. Close
the valve hand tight.5. Remove the fuel-resistant container and properly
dispose of the contaminated fuel. To find out how
to properly dispose of contaminated diesel fuel, see
Engine Oil (Caterpillar
®Diesel Engine) on
page 5-20orEngine Oil (Gasoline Engine) on
page 5-20orEngine Oil (DURAMAX™ Diesel) on
page 5-25for more information.
6. Install the fuel cap.
7. Start the engine and let it run for a few minutes. If
the engine stalls, the fuel system may need to be
primed. While draining the water from the fuel filter,
air may enter the fuel system. If air has entered
the fuel system the fuel system will need to
be primed.
If the water in fuel light comes on again after driving a
short distance or the engine runs rough or stalls, a large
amount of water has probably been pumped into the
fuel tank. The fuel tank should be purged.
5-12
Fuel Priming
In order for the DURAMAX™ diesel engine fuel system
to work properly, the fuel lines must be full of fuel
and contain no air. If air gets into the fuel lines, it will be
necessary to prime the fuel lines to eliminate air
before operating the vehicle.
Q:How does air get into the fuel lines?
A:One of the following may have happened:
•The vehicle ran out of fuel, or
•The fuel filter was removed for servicing or
replacement, or
•The fuel lines were removed or disconnected for
servicing, or
•The fuel filter water drain valve was opened while
the engine was running.If one or more of the above occur, it is very likely that
air has entered your fuel system and that you will need
to prime the fuel system before operating the vehicle.
Air in the fuel lines will not harm the engine or the
vehicle.
However, the engine may not be able to start until the
fuel system is primed and the air is removed.
Q:How do I prime the vehicle?
A:Your vehicle is equipped with the priming pump
which is part of the engine mounted fuel filter. The
vent valve and the fuel filter primer pump are
located on top of the fuel filter housing. The
priming pump is hand operated and is designed to
bring fuel to the engine to eliminate any air that
may be in the fuel lines.
To prime the engine, do the following:
1. Make sure there is fuel in the tank.
2. Make sure the fuel filter had been installed and
properly tightened.
5-13