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Checking Coolant for Gasoline Engines
If your vehicle has a diesel engine, see “Checking
Coolant” under “Van Models” in the DURAMAX®
Diesel Supplement for information on checking
your vehicle’s coolant.
The coolant recovery
tank is located near the
center of the engine
compartment. See
Engine Compartment
Overview on page 296
for more information
on location.
The vehicle must be on a level surface. When
your engine is cold, the coolant level should be at
the COLD FILL mark, or a little higher.
Adding Coolant
If you need more coolant, add the proper
DEX-COOL®coolant mixture at the coolant
recovery tank, but be careful not to spill it.
{CAUTION:
Turning the radiator pressure cap when
the engine and radiator are hot can allow
steam and scalding liquids to blow out
and burn you badly. With the coolant
recovery tank, you will almost never
have to add coolant at the radiator. Never
turn the radiator pressure cap — even
a little — when the engine and radiator
are hot.
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{CAUTION:
You can be burned if you spill coolant
on hot engine parts. Coolant contains
ethylene glycol, and it will burn if the
engine parts are hot enough. Do not spill
coolant on a hot engine.
Occasionally check the coolant level in the
radiator. For information on how to add coolant to
the radiator, seeCooling System on page 311.
Radiator Pressure Cap
The radiator pressure cap is located near the
center of the engine compartment. SeeEngine
Compartment Overview on page 296for more
information on location.
Notice:If the pressure cap is not tightly
installed, coolant loss and possible engine
damage may occur. Be sure the cap is properly
and tightly secured.
Engine Overheating
You will find an engine coolant temperature gage
on your vehicle’s instrument panel. SeeEngine
Coolant Temperature Gage on page 178for more
information.
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Page 317 of 452

Engine Fan Noise
Your vehicle has a clutched engine cooling fan.
When the clutch is engaged, the fan spins faster to
provide more air to cool the engine. In most
everyday driving conditions, the fan is spinning
slower and the clutch is not fully engaged.
This improves fuel economy and reduces fan
noise. Under heavy vehicle loading, trailer towing,
and/or high outside temperatures, the fan speed
increases as the clutch more fully engages, so you
may hear an increase in fan noise. This is
normal and should not be mistaken as the
transmission slipping or making extra shifts. It is
merely the cooling system functioning properly.
The fan will slow down when additional cooling is
not required and the clutch partially disengages.
You may also hear this fan noise when you
start the engine. It will go away as the fan clutch
partially disengages.
Power Steering Fluid
The power steering fluid
reservoir is located in
the engine compartment
on the driver’s side of
the vehicle. SeeEngine
Compartment Overview
on page 296for
reservoir location.
When to Check Power Steering Fluid
It is not necessary to regularly check power
steering fluid unless you suspect there is a leak in
the system or you hear an unusual noise. A
fluid loss in this system could indicate a problem.
Have the system inspected and repaired.
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How to Check Power Steering Fluid
To check the power steering fluid, do the following:
1. Turn the key off and let the engine
compartment cool down.
2. Wipe the cap and the top of the
reservoir clean.
3. Unscrew the cap and wipe the dipstick with a
clean rag.
4. Replace the cap and completely tighten it.
5. Then remove the cap again and look at
the fluid level on the dipstick.
The level should be at the COLD FILL mark. If
necessary, add only enough fluid to bring the level
up to the mark.
To prevent contamination of brake fluid, never
check or fill the power steering reservoir with the
brake master cylinder cover off.
What to Use
To determine what kind of fluid to use, see
Recommended Fluids and Lubricants on page 409.
Always use the proper fluid. Failure to use the
proper fluid can cause leaks and damage hoses
and seals.
Windshield Washer Fluid
What to Use
When you need windshield washer fluid, be sure to
read the manufacturer’s instructions before use. If
you will be operating your vehicle in an area where
the temperature may fall below freezing, use a fluid
that has sufficient protection against freezing.
Adding Washer Fluid
Open the cap with the
washer symbol on it.
Add washer fluid
until the tank is full. See
Engine Compartment
Overview on page 296
for reservoir location.
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So, it is not a good idea to top off your brake fluid.
Adding brake fluid will not correct a leak. If you
add fluid when your linings are worn, then you will
have too much fluid when you get new brake
linings. You should add or remove brake fluid, as
necessary, only when work is done on the
brake hydraulic system.
{CAUTION:
If you have too much brake uid, it can
spill on the engine and/or fuel operated
heater parts, if equipped. If your vehicle
has a diesel engine and a fuel operated
heater, see “Fuel Operated Heater (FOH)”
in the diesel engine supplement. The uid
will burn if the engine is hot enough. You
or others could be burned, and your
vehicle could be damaged. Add brake
uid only when work is done on the brake
hydraulic system. See “Checking Brake
Fluid” in this section.Refer to the Maintenance Schedule to determine
when to check your brake fluid. SeeScheduled
Maintenance (Gasoline Engine) on page 399.
Checking Brake Fluid
You can check the brake fluid without taking off
the cap.
Look at the brake fluid
reservoir. The fluid level
should be above
MIN. If it is not, have
your brake system
checked to see if
there is a leak.
After work is done on the brake hydraulic system,
make sure the level is above the MIN but not
over the MAX mark.
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{CAUTION:
Fans or other moving engine parts can
injure you badly. Keep your hands away
from moving parts once the engine is
running.
5. Check that the jumper cables do not have
loose or missing insulation. If they do, you
could get a shock. The vehicles could
be damaged too.
Before you connect the cables, here are some
basic things you should know. Positive (+)
will go to positive (+) or to a remote positive (+)
terminal if the vehicle has one. Negative (−)
will go to a heavy, unpainted metal engine part
or to a remote negative (−) terminal if the
vehicle has one.
Do not connect positive (+) to negative (−)or
you will get a short that would damage
the battery and maybe other parts too. And do
not connect the negative (−) cable to the
negative (−) terminal on the dead battery
because this can cause sparks.6. Connect the red positive (+) cable to the
positive (+) terminal of the dead battery.
Use a remote positive (+) terminal if
the vehicle has one.
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All-Wheel Drive
Lubricant checks in this section also apply to
these vehicles. However, there are two additional
systems that need lubrication.
Transfer Case
When to Check Lubricant
Refer to the Maintenance Schedule to determine
how often to check the lubricant. SeeScheduled
Maintenance (Gasoline Engine) on page 399.
How to Check Lubricant
To get an accurate reading, the vehicle should be
on a level surface.If the level is below the bottom of the filler plug
hole, you’ll need to add some lubricant. Add
enough lubricant to raise the level to the bottom of
the filler plug hole. Use care not to overtighten
the plug.
What to Use
Refer to the Maintenance Schedule to determine
what kind of lubricant to use. SeeRecommended
Fluids and Lubricants on page 409.
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Rear Axle
When to Check Lubricant
Refer to the Maintenance Schedule to determine
how often to check the lubricant. SeeScheduled
Maintenance (Gasoline Engine) on page 399.
How to Check Lubricant
To get an accurate reading, the vehicle should be
on a level surface.If you have the 1500 Series, the proper level is
from 5/8 inch (15 mm) to 1 5/8 inch (40 mm) below
the bottom of the filler plug hole. The proper
level for the 2500 and 3500 Series is from
0 to 1/4 (6 mm) below the bottom of the filler
plug hole. Add only enough fluid to reach
the proper level.
What to Use
Refer to the Maintenance Schedule to determine
what kind of lubricant to use. SeeRecommended
Fluids and Lubricants on page 409.
Front Axle
When to Check and Change Lubricant
Refer to the Maintenance Schedule to determine
how often to check the lubricant and when to
change it. SeeScheduled Maintenance (Gasoline
Engine) on page 399.
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