A. Battery. SeeBattery on page 6-43.
B. Radiator Pressure Cap. SeeCooling System on
page 6-28.
C. Coolant Recovery Tank. SeeCooling System on
page 6-28.
D. Automatic Transmission Fluid Dipstick. See
“Checking the Fluid Level” underAutomatic
Transmission Fluid (4-Speed Transmission)
on page 6-21orAutomatic Transmission Fluid
(6-Speed Transmission) on page 6-24.
E. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 6-15.
F. Engine Oil Dipstick. See “Checking Engine Oil”
underEngine Oil on page 6-15.
G. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 6-20.
H. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 6-38.
I. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 6-40.
J. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 6-39.Engine Oil
For diesel engine vehicles, see “Engine Oil” in the
DURAMAX®Diesel manual.
Checking Engine Oil
It is a good idea to check the engine oil level at each
fuel fill. In order to get an accurate reading, the oil must
be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop.
SeeEngine Compartment Overview on page 6-14
for the location of the engine oil dipstick.
1. Turn off the engine and give the oil several minutes
to drain back into the oil pan. If this is not done, the
oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
6-15
Cooling System
If your vehicle has a diesel engine, see “Van Models”
under “Cooling System” in the DURAMAX®Diesel
Supplement.
The Cooling System allows the engine to maintain the
correct working temperature.
A. Radiator Pressure Cap
B. Coolant Recovery Tank
C. Engine Cooling Fan(s)
{WARNING:
An electric engine cooling fan under the hood can
start up even when the engine is not running and
can cause injury. Keep hands, clothing, and tools
away from any underhood electric fan.
{WARNING:
Heater, fuel operated heater (FOH), radiator
hoses, and other engine parts, can be very hot.
Do not touch them. If you do, you can be burned.
WARNING: (Continued)
6-28
WARNING: (Continued)
Do not run the engine if there is a leak. If you run
the engine, it could lose all coolant. That could
cause an engine fire, and you could be burned.
Get any leak fixed before you drive the vehicle.
Notice:Using coolant other than DEX-COOL may
cause premature engine, heater core, radiator and
fuel operated heater (FOH) corrosion. In addition, the
engine coolant may require changing sooner, at
30,000 miles (50 000 km) or 24 months, whichever
occurs rst. Any repairs would not be covered by
your warranty. Always use DEX-COOL (silicate-free)
coolant in your vehicle.
Engine Coolant
The cooling system in the vehicle is filled with
DEX-COOL®engine coolant. This coolant is designed
to remain in the vehicle for five years or 150,000 miles
(240 000 km), whichever occurs first.
The following explains the cooling system and how to
check and add coolant when it is low. If there is a problem
with engine overheating, seeEngine Overheating on
page 6-35.
6-29
If the temperature overheat gage is no longer in the
overheat zone or an overheat warning no longer
displays, the vehicle can be driven. Continue to drive
the vehicle slow for about 10 minutes. Keep a safe
vehicle distance from the car in front of you. If the
warning does not come back on, continue to drive
normally.
If the warning continues, pull over, stop, and park the
vehicle right away.
If there is still no sign of steam, push down the
accelerator until the engine speed is about twice
as fast as normal idle speed for at least three minutes
while you are parked. If you still have the warning,
turn off the engine until it cools down.
You may decide not to lift the hood but to get service
help right away.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.
6-37
Brakes
Brake Fluid
The brake master cylinder
reservoir is filled with
DOT 3 brake fluid. See
Engine Compartment
Overview on page 6-14for
the location of the reservoir.
There are only two reasons why the brake fluid level in
the reservoir might go down:
•The brake fluid level goes down because of normal
brake lining wear. When new linings are installed,
the fluid level goes back up.
•A fluid leak in the brake hydraulic system can also
cause a low fluid level. Have the brake hydraulic
system fixed, since a leak means that sooner
or later the brakes will not work well.Do not top off the brake fluid. Adding fluid does not
correct a leak. If fluid is added when the linings are worn,
there will be too much fluid when new brake linings are
installed. Add or remove brake fluid, as necessary, only
when work is done on the brake hydraulic system.
{WARNING:
If too much brake fluid is added, it can spill on
the engine and/or fuel operated heater parts, if
equipped. If the vehicle has a diesel engine and a
fuel operated heater, see “Fuel Operated Heater
(FOH)” in the diesel engine supplement. The fluid
will burn if the engine is hot enough. You or others
could be burned, and the vehicle could be
damaged. Add brake fluid 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 the brake fluid. SeeScheduled Maintenance
on page 7-3.
6-40
Among those acts presumed to constitute tampering are
the acts listed below.
Insulation:
•
Removal of the noise shields or any underhood
insulation.
Engine:
•
Removal or rendering engine speed governor, if the
vehicle has one, inoperative so as to allow engine
speed to exceed manufacturer specifications.
Fan and Drive:
•
Removal of fan clutch, if the vehicle has one, or
rendering clutch inoperative.
•Removal of the fan shroud, if the vehicle has one.
Air Intake:
•
Removal of the air cleaner silencer.
•Modification of the air cleaner.
Exhaust:
•
Removal of the muffler and/or resonator.
•Removal of the exhaust pipes and exhaust pipe
clamps.
Fuel Operated Heater (FOH) — Diesel
Engine:
•
Removal of the muffler.
6-52