CHEVROLET C/K 2003 Owners Manual

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.

6-11
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 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 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.
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.

6-12
5. Open the fuel filter vent
valve by turning the
screw counterclockwise
several full turns.
6. Repeatedly press down
on the fuel filter primer
pump with the palm
of your hand. Let the
pump return upward
between presses.7. Operate the priming pump until a small amount of
fuel seeps from the vent valve. When you see the
fuel, the filter is now full of fuel and the system
should be primed.
8. Close the vent valve.
9. Clean any fuel which accumulated on the fuel filter.
10. Start the engine and let it idle for a few minutes.
11. Check the filter for leaks.

6-13 Running Out of Fuel (Diesel Engines)
If the engine stalls and you think that you've run out of
fuel, do this:
CAUTION:
Diesel fuel is flammable. It could start a fire if it
gets on hot engine parts. You could be burned.
Don't let too much fuel flow from the air bleed
valve, and wipe up any spilled fuel with a cloth.
To restart your engine:
1. If you're parked on a level surface, add at least two
gallons of fuel to each fuel tank your vehicle may
have. However, if you're parked on a slope, you may
need to add up to five gallons of fuel.
2. Follow the fuel priming procedure earlier in this
section to prime the fuel filter.
3. Close the air bleed valve
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.

6-14 Fuel Filter Replacement (Diesel Engines)
If you want to change the fuel filter yourself, here's how
to do it:
CAUTION:
Diesel fuel is flammable. It could start a fire if
something ignites it, and you could be burned.
Don't let it get on hot engine parts, and keep
matches or other ignition sources away.
First, drain any water from the filter following the
procedure for draining water listed previously.
Your vehicle's engine should be off until the end of
this procedure.
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 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. 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.

6-15
Fuels in Foreign Countries
(Gasoline Engines)
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.
Filling Your Tank
C4/C5 Models

6-16
C6/C7/C8 Models
CAUTION:
Fuel vapor is highly flammable. It burns
violently, and that can cause very bad injuries.
Don't smoke if you're near fuel or refueling your
vehicle. Keep sparks, flames and smoking
materials away from fuel.
The fuel cap can be on either or both sides of your
vehicle depending on option content.
To take off the cap, turn it slowly to the left
(counterclockwise).
CAUTION:
Gasoline Engine Vehicles: If you get gasoline on
you and then something ignites it, you could be
badly burned. Gasoline can spray out on you if
you open the fuel cap too quickly. This spray can
happen if your tank is nearly full, and is more
likely in hot weather. Open the fuel filler cap
slowly and wait for any ªhissº noise to stop. Then
unscrew the cap all the way.
When you put the cap back on, turn it to the right
(clockwise) until it is tight.