2003 CHEVROLET C/K Owners Manual

6-3 Two Safety Cautions about Engine
Fan Breakage
CAUTION:
Changing the Fan Drive Ratio or Engine
Governed Speed
If you change the fan drive ratio or increase the
governed speed of the engine, you may increase
stress on the engine fan and the fan could
eventually fail. If the fan breaks apart while it is
rotating, the flying pieces can cause severe injury
to anyone
-- such as a service technician -- who is
nearby. And, of course, the pieces can severely
damage the vehicle. Don't change the fan drive
ratio or increase the governed speed of the
vehicle without getting the necessary information
from your dealer.
CAUTION: (Continued)
CAUTION: (Continued)
Winter Fronts, Grille Covers or Obstructions
Winter fronts, grille covers or other add-on
equipment causing obstructions in front or
behind the fan should not be used on this vehicle.
They may increase the stress on the fan as the
blades pass over the covered areas. If this causes
the fan to eventually break apart while it is
rotating, the pieces can cause severe injury to
anyone nearby, such as a service technician
working on the engine, and of course the pieces
can severely damage the vehicle.

6-4
Fuel (Gasoline Engine)
If your vehicle has a diesel engine, see ªDiesel Engine
Fuelº in this section. 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 it is bad
enough, it can 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.
Gasoline Specifications
It is recommended that gasoline meet specifications
which were developed by the American Automobile
Manufacturers Association and endorsed by the
Canadian Vehicle Manufacturers' Association for better
vehicle performance and engine protection. Gasolines
meeting these specifications could provide improved
driveability and emission control system performance
compared to other gasolines.
In Canada, look for
the ªAuto Makers'
Choiceº label on
the pump.
Canada Only
Additives
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.

6-5
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.
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. Don't use fuel containing
methanol. It can corrode metal parts in your
fuel system and also damage plastic and rubber
parts. That damage wouldn't be covered under
your warranty.
Diesel Fuel Requirements and
Fuel System
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 wouldn't cover this
damage. And:

Diesel fuel that has been mixed with engine
oil could damage your engine and emission
controls.

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, ªRunning Out of Fuel,º later in
this section, tells you how to restart your engine.

6-6 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
-00 (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.Diesel fuel may foam when you fill your tank. This can
cause the automatic pump nozzle to shut off, even
though your tank isn't 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 fire could start and
people could be burned. To help avoid this, fill
your fuel tank only until the automatic nozzle
shuts off. Don't try to ªtop it off.º

6-7
What Fuel to Use in Canada
Canadian fuels are blended for seasonal changes. Diesel
Type ªAº 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 ªAº fuel is used
in warmer temperatures, stalling and hard starting may
occur. Diesel Type ªBº 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.
Very Cold Weather Operation
Follow the instructions listed previously under the
heading ªWhat Fuel to Use.º
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 won't need to replace it.
Additional information on the fuel filter follows.

6-8 Water in Fuel
CAUTION:
Diesel fuel containing water is still flammable.
You could be burned. If you ever try to drain
water from your fuel, keep sparks, flames 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. You'll need a diesel fuel biocide to
sterilize your fuel system. Your dealer can advise
you if you ever need this.
If your fuel tank needs to be purged to remove
water, see your dealer or a qualified 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 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 indicator
will come on. If it does,
the water must be drained.
Your dealer can show you
how to do this.

6-9
If it comes on, use this chart.
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.
Water In Fuel Indicator Chart
Problem
Recommended Action
Indicator comes
on intermittently.Drain water from fuel filter.
Indicator
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.

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.

Immediately
after refueling,
large amount of
water possibly
pumped into
fuel tank.Fuel tank purging required. See
your dealer for assistance.

6-10
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
ªWhat to Do with Used Oilº in the ªEngine Oil
(Diesel Engines)º part, later in this section.
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.
Refer to ªFuel Primingº later in this section.
If the water in fuel indicator 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
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.