If you are trying to start your engine after you have run
out of fuel, seeRunning Out of Fuel on page 5-15.
When your engine is cold, let it run for a few minutes
before you move your vehicle. This lets oil pressure
build up. Your engine will sound louder when it is cold.
Notice:If you are not in an idling vehicle and
the engine overheats, you would not be there to
see the overheated engine indication. This could
damage your vehicle. Do not let your engine
run when you are not in your vehicle.
Cold Weather Starting
If your vehicle has the DURAMAX®Diesel Engine,
the following notice applies:
Notice:Your diesel engine has an electric air intake
heater system which reduces white smoke and helps
start the engine in cold weather. Do not spray
starting uid into the air intake where it can contact
the heater elements.If you do not have the GM Automatic Ether Injection
System, do not use starting uid or you could
damage your engine. If you have the GM system,
use only GM approved starting uid that has been
tested to establish compatibility with the air inlet
heater system.
The following tips will help you get good starting in
cold weather.
•Use the recommended engine oil when the outside
temperature drops below freezing. SeeEngine Oil
(Caterpillar
®Diesel Engine) on page 5-22or
Engine Oil (DURAMAX®Diesel) on page 5-22or
Engine Oil (Gasoline Engine) on page 5-26.
When the outside temperature drops below
0°F (−18°C), use of the optional engine coolant
block heater is recommended.
•If you experience longer cranking times, notice an
unusual amount of exhaust smoke or are at
higher altitudes (over 7,000 ft. or 2 135 m), you may
use your optional engine coolant block heater.
SeeEngine Coolant Heater on page 2-24.
•SeeWhat Fuel to Use on page 5-8for information
on what fuel to use in cold weather.
2-16
During this warm-up period, check your warning lights
and gages:
•If oil pressure does not begin to rise within
15 seconds of starting, stop the engine and find the
cause. SeeOil Pressure Gage on page 3-37for
more information.
•If the engine coolant temperature gage needle goes
into the hot area on the gage, stop the engine and
find the cause of the overheating. SeeEngine
Coolant Temperature Gage on page 3-35for
more information.
•If you have air brakes, the dual-needle air pressure
gage should read at least 115 psi (790 kPa) for
both service systems before you try to move
the vehicle. When air pressure is below 60 psi
(420 kPa), the LOW AIR light will come on and you
will hear a tone alarm. SeeBrake System Warning
Light on page 3-31for more information. If the
pressure does not build up or drops during warm-up,
stop the engine and find the cause before you try
to move the vehicle. Recommended air pressure
before driving is 120 psi (830 kPa). SeeAir
Pressure Gage on page 3-44for more information.
•The charging system light should come on when
the ignition key is turned to RUN or START and
should go out when the engine is running above
idle. If the light does not go out or comes back on
during normal engine operation, have the charging
system checked right away. (This light tells you
if the generator is not charging; it does not reflect
the condition of the battery.) SeeCharging System
Light on page 3-30for more information.
•The voltmeter charge indicator gage tells you the
condition of your battery’s charge. The gage
should be in the center area during engine
operation. The red area on the left indicates an
undercharge condition; the red area on the
right indicates an overcharge. If the gage is in
either red area, have the battery and charging
system checked right away. SeeVoltmeter Gage
on page 3-30for more information.
Notice:Do not allow the engine to operate at low
idle for more than ve minutes. This can cause
low engine operating temperatures which can
affect engine operation and reduce engine life.
Engine idle speed should be increased to 1200 rpm
whenever extended idle is required. Once started,
the engine should be placed under load to allow the
engine coolant temperature to reach 150°F (66°C)
before shutting off the engine.
2-23
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.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 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 5-15
tells you how to restart your engine.
5-7
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 D975-03 (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.
If your vehicle has the 6.6L engine, it is acceptable
to use diesel fuel containing up to 5% biodiesel (B5), but
the final blended fuel must meet the same specification,
ASTM D975-03 (Grade Low Sulfur), as other fuels
used in your vehicle, and the biodiesel used for making
this fuel must meet the ASTM D6751-03 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.
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.
5-8
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.If your vehicle has the 6.6L engine, 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 D6751-03 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.
5-9
3. Remove the filter element. If there is any dirt on the
filter sealing surface, clean it off. Remove and
reuse the water sensor float switch located on the
bottom of the fuel filter.
4. Install the new filter element.
5. Reinstall and tighten the filter container and
reconnect the water sensor wire to the filter.
6. Use the fuel filter priming procedure earlier in this
section to prime the fuel filter.
7. Tighten the air bleed valve by turning it clockwise
until hand-tight.
8. Start your engine and let it idle for five minutes.
Check your fuel filter and air bleed valve for leaks.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 find. Never use leaded gasoline or any other
fuel not recommended in the previous text on fuel.
Costly repairs caused by use of improper fuel wouldn’t
be covered by your warranty.
To check on fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you’ll be driving.
5-17
What Kind of Engine Oil to Use
Look for these two things:
•CI-4 or CH-4
Oils designated as API CI-4 or CH-4 are
recommended for your vehicle. The CI-4 or CH-4
designations may appear either alone, together or in
combination with other API designations, such as
API CI-4/SL.
These letters show American Petroleum Institute
(API) levels of quality.
Notice:Use only engine oils that have one of these
designations CI-4 or CH-4 for the DURAMAX
®
diesel engine. Failure to use the recommended oils
can result in engine damage not covered by your
warranty.
5-24
•SAE 15W-40
As shown in the viscosity chart, SAE 15W-40 is
best for your vehicle. However, you can use
SAE 10W-30 at temperatures above 0°F (−18°C).
When it is very cold, below 0°F (−18°C), you should
use SAE 5W-40 to improve cold starting.
These numbers on the oil container show its
viscosity, or thickness. Do not use other viscosity
oils such as SAE 10W-40 or SAE 20W-50.
This doughnut-shaped
logo (symbol) is used on
most oil containers to
help you select the correct
oil. It means that the oil
has been certified by
the American Petroleum
Institute.
You should look for this on the oil container, and use
onlythose oils that display this logo.
GM Goodwrench
®oil of the recommended viscosity
grades meets all the requirements for your vehicle.
Engine Oil Additives
Do not add anything to your oil. The recommended oils
with the API service symbol are all you will need for
good performance and engine protection.
When to Change Engine Oil (Vehicles
Without the Engine Oil Life System)
If you have the 6.6L V8 (LLY) Engine: Change engine
oil and filter every 15,000 miles (24 000 km), or
every 12 months, or every 750 hours of engine
operation, whichever occurs first. If you have the
7.8L V6 (LG4) Engine: Change engine oil and filter
every 12,000 miles (20 000 km), or every 12 months,
or every 600 hours of engine operation, whichever
occurs first. SeeScheduled Maintenance on page 6-5.
5-25