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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 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.
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Page 217 of 384

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/retailer 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/retailer 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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Page 218 of 384

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
Engine Oil (Caterpillar
®Diesel Engine) on
page 5-23orEngine Oil (Gasoline Engine) on
page 5-24orEngine Oil (DURAMAX
®Diesel Engine)
on page 5-28orEngine Oil (Isuzu Diesel Engine) on
page 5-32.
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
®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.
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.
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Page 254 of 384
Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Engine Fan
B. Coolant Surge Tank
If 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.
5-50