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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 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 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 can advise you of the
appropriate solution.
If your fuel tank needs to be purged to remove
water, see your dealer 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
can show you how to
do this.
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If the light comes on, use this chart to determine
what action to take.
Water In Fuel Light
Problem Recommended Action
Light comes on
intermittently.Drain water from the
fuel filter.
Light stays on at
temperatures above
freezing.Drain the fuel filter
immediately. If no water
can be drained and the
light stays on, see your
dealer for assistance.
Light stays on at
temperatures below
freezing.Drain the fuel filter
immediately. If no water
can be drained, water
may be frozen in the
water drain system, or in
the fuel lines. Move the
vehicle to a warm location
to thaw out, and then
drain the filter system.
Light stays on
immediately after
refueling, and a large
amount of water was
possibly pumped into the
fuel tank.Fuel tank purging is
required. See your dealer
for assistance.
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.
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.
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.
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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, seeEngine Oil
(Caterpillar
®Diesel Engine) on page 268or
Engine Oil (Gasoline Engine) on page 268or
Engine Oil (DURAMAX
®/Isuzu Diesel
Engine) on page 272.6. 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.
If the water-in-fuel light 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
If your vehicle has a Caterpillar®diesel engine,
see the Caterpillar®Diesel Engine Operation and
Maintenance Manual provided with your vehicle.
If your vehicle has a DURAMAX
®/Isuzu diesel
engine, in order for the 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.
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Air can get into the fuel lines if any of the following
happen:
•The vehicle runs out of fuel.
•The fuel filter is removed for servicing or
replacement.
•The fuel lines are removed or disconnected
for servicing.
•The fuel filter water drain valve is opened
while the engine is running.
If one or more of the above occurred, 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.
Priming the 6.6L DURAMAX®Diesel
Engine
If your vehicle is equipped with the 6.6L
DURAMAX®diesel engine, it has 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 6.6L DURAMAX
®diesel 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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Cooling System (Gas and
DURAMAX
®/Isuzu Engines)
When you decide it is safe to lift the hood, here is
what you will see:
A. Engine Fan
B. Coolant Surge TankIf your vehicle has a Caterpillar
®diesel engine,
see the Caterpillar®Diesel Engine Operation and
Maintenance Manual provided with your vehicle.
If the coolant inside the coolant surge tank is
boiling, do not do anything else until it cools down.
The vehicle should be parked on a level surface.
The coolant level should
be at the FULL COLD
mark or higher. If it is
not, you may have a leak
at the pressure cap or in
the radiator hoses,
heater hoses, radiator,
water pump, or
somewhere else in the
cooling system.
290