2003 CHEVROLET C/K Owners Manual

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.

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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.

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NOTICE:
If you need a new fuel cap, be sure to get the
right type. Your dealer can get one for you. If you
get the wrong type, it may not fit or have proper
venting, and your fuel tank and emissions system
might be damaged.
If you have dual tanks, fill the driver's side tank, or
forward tank, first. The fuel gage will give better
readings this way. Your gage will show the average level
of both tanks combined.
Filling a Portable Fuel Container
CAUTION:
Never fill a portable fuel container while it is in
your vehicle. Static electricity discharge from the
container can ignite the gasoline vapor. You can
be badly burned and your vehicle damaged if this
occurs. To help avoid injury to you and others:

Dispense gasoline only into approved
containers.

Do not fill a container while it is inside a
vehicle, in a vehicle's trunk, pickup bed or
on any surface other than the ground.

Bring the fill nozzle in contact with the
inside of the fill opening before operating
the nozzle. Contact should be maintained
until the filling is complete.

Don't smoke while pumping gasoline.

6-18
Checking Things Under the Hood
CAUTION:
Things that burn can get on hot engine parts and
start a fire. These include liquids like fuel, oil,
coolant, brake fluid, windshield washer and other
fluids, and plastic or rubber. You or others could
be burned. Be careful not to drop or spill things
that will burn onto a hot engine.
Hood Latches
To tilt the hood forward, pull back and up on each of the
hood latches, located above the wheel wells on both
sides of the vehicle.