Page 209 of 376

Gasoline Specifications
At a minimum, gasoline should meet ASTM specification
D 4814 in the United States or CAN/CGSB-3.5 or 3.511 in
Canada. Some gasolines contain an octane-enhancing
additive called methylcyclopentadienyl manganese
tricarbonyl (MMT). We recommend against the use of
gasolines containing MMT. SeeAdditives on page 5-7
for additional information.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that help prevent
engine and fuel system deposits from forming, allowing
the emission control system to work properly. In most
cases, you should not have to add anything to the fuel.
However, some gasolines contain only the minimum
amount of additive required to meet U.S. Environmental
Protection Agency regulations. To help keep fuel injectors
and intake valves clean, or if the vehicle experiences
problems due to dirty injectors or valves, look for gasoline
that is advertised as TOP TIER Detergent Gasoline.
For customers who do not use TOP TIER Detergent
Gasoline regularly, one bottle of GM Fuel System
Treatment PLUS, added to the fuel tank at every engine
oil change, can help clean deposits from fuel injectors
and intake valves. GM Fuel System Treatment PLUS is
the only gasoline additive recommended by General
Motors.Also, your dealer/retailer has additives that will help
correct and prevent most deposit-related problems.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines might be available in
your area. We recommend that you use these gasolines,
if they comply with the specifications described earlier.
However, E85 (85% ethanol) and other fuels containing
more than 10% ethanol must not be used in vehicles that
were not designed for those fuels.
Notice:This vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in the fuel
system and also damage plastic and rubber parts.
That damage would not be covered under the
vehicle warranty.
Some gasolines that are not reformulated for low
emissions can contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. We recommend against
the use of such gasolines. Fuels containing MMT can
reduce the life of spark plugs and the performance of
the emission control system could be affected. The
malfunction indicator lamp might turn on. If this occurs,
return to your dealer/retailer for service.
5-7
Page 210 of 376

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 the fuel
system and engine. Your warranty would not
cover this damage. And:
•Diesel fuel that has been mixed with engine oil
or automatic transmission fluid could damage
the engine and emission controls.
•We do not test aftermarket diesel fuel additives.
Some additives, particularly those which
contain alcohol or water emulsifiers, could
damage the fuel system. If you believe that
unique circumstances call for a fuel additive to
be used, consult your dealer/retailer for
advice.
•If you ever run out of diesel fuel, it can be
difficult to restart the engine. To avoid this,
never let the tank get empty.
If gasoline is ever accidentally added to the fuel
tank, to avoid severe engine damage, do not run the
engine until the fuel tank can be drained.
If you run out of fuel,Running Out of Fuel on page 5-17
tells you how to restart the engine.
What Fuel to Use
Notice:Use of diesel fuel other than Ultra Low
Sulfur Diesel (15 ppm sulfur maximum) or engine oil
other than low ash CJ-4 oil will cause permanent
damage to the DPF and related components. This
damage would not be covered by your warranty.
The emission control system requires the use of diesel
fuel with ultra low-sulfur (0.0015% by weight, or 15 ppm,
maximum) content. Both Ultra Low Sulfur Diesel and Low
Sulfur Diesel fuels are available in the United States and
Ultra Low Sulfur Diesel fuel is available in Canada. In
Mexico, Ultra Low Sulfur Diesel fuel is not available in all
regions.
At a minimum, the diesel fuel you use should meet the
latest version of ASTM specification D 975 (Grades
No. 2-D or No. 1-D S15 commonly known as Ultra Low
Sulfur diesel) 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.
5-8
Page 211 of 376

In the United States, for best results use No. 2-D diesel
fuel year-round (above and below freezing conditions) as
oil companies blend No. 2-D fuel to address climate
differences. No. 1-D diesel fuel can 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 No. 1-D diesel fuel in warm or hot
climates. It can result in stalling, poor starting when the
engine is hot, and could damage the fuel injection
system.
It is acceptable to use diesel fuel containing up to
5% biodiesel (B5), but the final blended fuel must meet
the same specification, ASTM D 975 (Grades No. 2-D or
No. 1-D S15 commonly known as Ultra Low Sulfur
diesel), as other fuels used in your vehicle, and the
biodiesel used for making this fuel must meet the latest
version of ASTM specification D 6751. Biodiesel is
produced from vegetable oils or animal fat that have been
chemically modified to reduce the possibility of damage
to the 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 the
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.Because of the cleansing properties of biodiesel,
switching from straight diesel to a biodiesel blend can
prematurely restrict the fuel filter with normal deposits in
the fuel system. A fuel filter replacement might be
required sooner than the recommended interval.
Diesel fuel can foam when you fill the tank. This can
cause the automatic pump nozzle to shut off, even
though the tank is not full. If this happens, just wait for
the foaming to stop and then try filling the tank more
slowly. SeeFilling the Tank on page 5-20.
{CAUTION:
Heat coming from the engine can cause the fuel to
expand and force the fuel out of the tank. If
something ignites the fuel, a fire could start and
people could be burned. To help avoid this, try
filling the tank more slowly and fill the fuel tank
only until the automatic nozzle shuts off. Do not try
to top it off.
5-9
Page 212 of 376

What Fuel to Use in Canada
Notice:Use of diesel fuel other than Ultra Low
Sulfur Diesel (15 ppm sulfur maximum) or engine oil
other than low ash CJ-4 oil will cause permanent
damage to the DPF and related components.
This damage would not be covered by your
warranty.
The emission control system requires the use of diesel
fuel with ultra low-sulfur (0.0015% by weight, or 15 ppm,
maximum) content. Both Ultra Low Sulfur Diesel and Low
Sulfur Diesel fuels are available in the United States and
Ultra Low Sulfur Diesel fuel is available in Canada. In
Mexico, Ultra Low Sulfur Diesel fuel is not available in all
regions.
At a minimum, the diesel fuel you use should meet the
latest version of specification CAN/CGSB-3.517 (ULS)
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.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 might 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).
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 (ULS) in
Canada, as other fuels used in your vehicle, and the
biodiesel used for making this fuel must meet the latest
version of ASTM specification D 6751. Biodiesel is
produced from vegetable oils or animal fat that have
been chemically modified to reduce the possibility
of damage to the 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 the 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.
5-10
Page 213 of 376

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 vehicle’s diesel engine. They can cause
engine damage.
In cold weather, the fuel filter could 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 flammable. You
could be burned. If you ever try to drain water
from the fuel, keep sparks, flames, and smoking
materials away from the mixture.Notice:If there is water in the diesel fuel and the
weather is warm or humid, fungus and bacteria can
grow in the fuel. They can damage the fuel system.
A diesel fuel biocide can be used to sterilize the
fuel system. However, the fuel system may still need
to be cleaned. Your dealer/retailer can advise you
of the appropriate solution.
If the fuel tank needs to be purged to remove water,
see your dealer/retailer or a qualified technician.
Improper purging can damage the fuel system.
Sometimes, water can be pumped into the fuel tank
along with the diesel fuel. This can happen if a service
station does not regularly inspect and clean its fuel
tanks, or if it gets contaminated fuel from its suppliers.
If this happens, the
water-in-fuel light, if
equipped, will come on in
the instrument panel. If it
does, the water must be
drained. Your dealer/
retailer can show you
how to do this.
If the light comes on, use this chart to determine what
action to take.
5-11
Page 214 of 376

Water In Fuel Light
Problem Recommended Action
Light comes on
intermittently.Drain water from the fuel
filter.
Light stays on at
temperatures above
freezing.Drain the fuel filter
immediately. If no water
can be drained and the
light stays on, see your
dealer/retailer for
assistance.
Light stays on at
temperatures below
freezing.Drain the fuel filter
immediately. If no water
can be drained, water
may be frozen in the
water drain system, or in
the fuel lines. Move the
vehicle to a warm location
to thaw out, and then
drain the filter system.
Light stays on
immediately after
refueling, and a large
amount of water was
possibly pumped into the
fuel tank.Fuel tank purging is
required. See your
dealer/retailer for
assistance.Notice:Driving when this warning indicator is on,
can damage the fuel injection system and the engine.
If the indicator comes on right after a refuel, it means
water was pumped into the fuel tank. Turn off the
engine immediately. Then, have the water drained
at once.
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.
If the vehicle has the 6.6L engine, the fuel filter is
located in the engine compartment on the driver side
of the vehicle. If the vehicle has either the 7.2L or
7.8L engine, the fuel filters are located in the engine
compartment on the driver side of the vehicle, and on
the driver side frame rail in front of the fuel tank.
5-12
Page 215 of 376

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 (DURAMAX Diesel Engine) on page 5-24
orEngine Oil (Caterpillar Diesel Engine) on
page 5-27orEngine Oil (Isuzu Diesel Engine) on
page 5-28orEngine Oil (Gasoline Engine) on
page 5-32.6. 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.
Fuel Priming
If the vehicle has a Caterpillar®diesel engine, see the
Caterpillar®Diesel Engine Operation and Maintenance
Manual provided with the vehicle.
If the vehicle has a DURAMAX
®diesel engine, in order
for the 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.
5-13
Page 216 of 376

Air can get into the fuel lines if any of the following
happen:
•The vehicle runs out of fuel.
•The fuel filter is removed for servicing or
replacement.
•The fuel lines are removed or disconnected for
servicing.
•The fuel filter water drain valve is opened while the
engine is running.
If one or more of the above occurred, it is very likely
that air has entered the fuel system and the fuel system
needs to be primed 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.
Priming the 6.6L Duramax®Diesel Engine
If the vehicle is equipped with the 6.6L Duramax®diesel
engine, it has a 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 in the fuel
lines.
To prime the 6.6L Duramax
®diesel 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.
3. Make sure the fuel lines are properly connected
and the fuel filter is cool enough to touch.
4. Remove any dirt from the fuel filter head and vent
valve by wiping with a cloth.
5-14