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 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/retailer
can advise you of the appropriate solution.
If your fuel tank needs to be purged to remove
water, see your dealer/retailer or a quali ed
technician. Improper purging can damage your fuel
system.
Sometimes, water can be pumped into your fuel tank
along with your 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.
5-12
4. Turn the ignition key to START for 10 to 15 seconds
at a time until your engine starts. If the engine tries
to run, but does not run smoothly, increase the rpm
a little using the accelerator pedal. This will help
force air through the system.
Your service engine soon light may come on if the
vehicle has run out of fuel. This light may stay on for a
few drive cycles after the condition is corrected, but
will eventually clear itself.
Fuel Filter Replacement
If you want to change the diesel engine fuel filter
yourself, here is how to do it:
{CAUTION:
Diesel fuel is ammable. It could start a re if
something ignites it, and you could be burned.
Do not let it get on hot engine parts, and keep
matches or other ignition sources away.
First, drain any water from the filter by following the
water draining procedure earlier in this section.
Your vehicle’s engine should be off until the end of this
procedure.If your vehicle has the 6.6L engine, the fuel filter is
located in the engine compartment on the driver’s side
of the vehicle. If your vehicle has either the 7.2L or
7.8L engine, the fuel filters are located in the engine
compartment on the driver’s side of the vehicle, and on
the driver’s side frame rail in front of the fuel tank.
1. Apply the parking brake.
2. Unplug the water
sensor wire connected
to the fuel filter and
unscrew the filter
element.
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.
5-18
Look for this information on the oil container, and use
only those oils that are identified as meeting GM
Standard GM6094M and have the starburst symbol on
the front of the oil container.
Notice:Use only engine oil identi ed as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certi ed For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.If you are in an area of extreme cold, where the
temperature falls below−20°F (−29°C), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE 0W-30 oil. Both provide easier
cold starting and better protection for the engine at
extremely low temperatures.
Engine Oil Additives
Do not add anything to the oil. The recommended oils
with the API service symbol are all you need for
good performance and engine protection.
5-27
•SAE 15W-40
As shown in the viscosity chart, SAE 15W-40 is best
for your vehicle. 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-30, 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.
Look for this on the oil container, and use only those
oils that display this logo.Engine Oil Additives
Do not add anything to the oil. The recommended oils
with the API service symbol are all you need for good
performance and engine protection.
When to Change Engine Oil (Vehicles
Without the Engine Oil Life System)
Change the 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. See
Scheduled Maintenance on page 6-5.
5-31
•SAE 10W-40 or SAE 15W-40
As shown in the viscosity chart, SAE 10W-40 or
SAE 15W-40 is best for your vehicle. 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-30 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.
Look for this on the oil container, and use only those
oils that display this logo.Engine Oil Additives
Do not add anything to the oil. The recommended oils
with the API service symbol are all you need for
good performance and engine protection.
When to Change Engine Oil (Vehicles
Without the Engine Oil Life System)
Change the 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 the vehicle
is used primarily for long trip, highway service, change
the engine oil and filter every 18,000 miles (28 800 km),
or every 12 months, or every 750 hours of engine
operation, whichever occurs first. SeeScheduled
Maintenance on page 6-5.
5-35
Engine Oil Life System (Gasoline
Engine)
When to Change Engine Oil
Your vehicle has a computer system that lets you know
when to change the engine oil and filter. This is based
on engine revolutions and engine temperature, and not
on mileage. Based on driving conditions, the mileage at
which an oil change will be indicated can vary
considerably. For the oil life system to work properly, you
must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A change engine oil light will come on. See
Change Engine Oil Light on page 3-38. Change the oil as
soon as possible within the next 600 miles (1 000 km).
It is possible that, if you are driving under the best
conditions, the oil life system might not indicate that an oil
change is necessary for over a year. However, the engine
oil and filter must be changed at least once a year and at
this time the system must be reset. Your dealer/retailer
has trained service people who will perform this work
using genuine parts and reset the system. It is also
important to check the oil regularly and keep it at the
proper level.If the system is ever reset accidentally, you must
change the oil at 3,000 miles (5 000 km) since your last
oil change. Remember to reset the oil life system
whenever the oil is changed.How to Reset the Engine Oil Life
System
The Engine Oil Life System calculates when to change
the engine oil and filter based on vehicle use. Whenever
the oil is changed, reset the system so it can calculate
when the next oil change is required. If a situation occurs
where you change the oil prior to a change engine oil light
being turned on, reset the system.
To reset the change engine oil light:
1. Turn the ignition key to ON/RUN with the
engine off.
2. Fully press and release the accelerator pedal slowly
three times within 10 seconds.
If the change engine oil light flashes for
five seconds, the system is resetting.
3. Turn the key to OFF.
If the change engine oil light comes back on when you
start your vehicle, the engine oil life system has not
reset. Repeat the procedure.
5-36
What to Do with Used Oil
Used engine oil contains certain elements that can be
unhealthy for your skin and could even cause cancer.
Do not let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good
hand cleaner. Wash or properly dispose of clothing or
rags containing used engine oil. See the manufacturer’s
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
filter before disposal. Never dispose of oil by putting it
in the trash, pouring it on the ground, into sewers, or into
streams or bodies of water. Instead, recycle it by
taking it to a place that collects used oil. If you have a
problem properly disposing of used oil, ask your
dealer/retailer, a service station, or a local recycling
center for help.
Engine Oil Life System
(DURAMAX
®/Isuzu Diesel Engines)
When to Change Engine Oil
If your vehicle has the Engine Oil Life System, it has a
computer system that lets you know when to change
the engine oil and filter. This is based on injection timing,
engine load and engine temperature, and not on
mileage. Based on driving conditions, the mileage atwhich an oil change will be indicated can vary
considerably. For the oil life system to work properly, you
must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A change engine oil light will come on. See
Change Engine Oil Light on page 3-38. Change the
oil as soon as possible within the next 600 miles
(1 000 km) or 30 hours of engine operation, whichever
occurs first. It is possible that, if you are driving under
the best conditions, the oil life system might not indicate
that an oil change is necessary for over a year. However,
the engine oil and filter must be changed at least once a
year and at this time the system must be reset. Your
dealer/retailer has trained service people who will
perform this work using genuine parts and reset the
system. It is also important to check the oil regularly and
keep it at the proper level.
If the system is ever reset accidentally, you must
change the oil at 15,000 miles (24 000 km), or 150 hours
of engine operation, whichever occurs first, since your
last oil change. Remember to reset the oil life system
whenever the oil is changed.
5-37
How to Reset the Engine Oil Life
System
The Engine Oil Life System calculates when to change
the engine oil and filter based on vehicle use. Whenever
the oil is changed, reset the system so it can calculate
when the next oil change is required. If a situation occurs
where you change the oil prior to a change engine oil light
being turned on, reset the system.
To reset the Engine Oil Life System:
1. Turn the ignition key to ON/RUN with the
engine off.
2. Fully press and release the accelerator pedal slowly
three times within five seconds.
If the change engine oil light is turned off, the
system is resetting.
3. Turn the key to OFF.
If the change engine oil light comes back on when you
start your vehicle, the Engine Oil Life System has not
reset. Repeat the procedure.
What to Do with Used Oil
Used engine oil contains certain elements that can be
unhealthy for your skin and could even cause cancer.
Do not let used oil stay on your skin for very long. Clean
your skin and nails with soap and water, or a good hand
cleaner. Wash or properly dispose of clothing or rags
containing used engine oil. See the manufacturer’s
warnings about the use and disposal of oil products.
Used oil can be a threat to the environment. If you
change your own oil, be sure to drain all the oil from the
filter before disposal. Never dispose of oil by putting it
in the trash, pouring it on the ground, into sewers, or into
streams or bodies of water. Instead, recycle it by taking
it to a place that collects used oil. If you have a problem
properly disposing of used oil, ask your dealer/retailer, a
service station, or a local recycling center for help.
5-38