2003 CHEVROLET SILVERADO Cooling system

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
·start your engine,
·shift into a gear, and
·release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission ¯uid (don't over®ll),
engine oil, axle lubricant, belt, cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you ®nd them quickly. If
you're trailering, it's a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
Your vehicle is equipped with one of the following wiring
harnesses for towing a trailer or hauling a slide-in
camper.
Basic Trailer Wiring
All regular, extended cab crew cab pickups have a
six-wire trailer towing harness.
The six-wire harness is located at the rear of the vehicle
and is tied to the vehicle's frame. The harness requires
the installation of a trailer-wiring harness connector,
which is available through your dealer.
4-89

Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside of Your
Vehicle......................................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-4
Gasoline Speci®cations....................................5-5
California Fuel...............................................5-5
Additives.......................................................5-5
Fuels in Foreign Countries...............................5-6
Filling Your Tank............................................5-6
Filling a Portable Fuel Container.......................5-8
Checking Things Under
the Hood......................................................5-8
Hood Release................................................5-9
Engine Compartment Overview.......................5-10
Engine Oil...................................................5-16
Engine Air Cleaner/Filter................................5-21
Automatic Transmission Fluid (Except Allison
Transmission
ž) ..........................................5-23Automatic Transmission Fluid (Allison
Transmission
ž) ..........................................5-26
Manual Transmission Fluid.............................5-28
Hydraulic Clutch...........................................5-29
Engine Coolant.............................................5-30
Coolant Surge Tank Pressure Cap..................5-33
Engine Overheating.......................................5-33
Cooling System............................................5-36
Engine Fan Noise.........................................5-41
Power Steering Fluid.....................................5-42
Windshield Washer Fluid................................5-43
Brakes........................................................5-44
Battery........................................................5-47
Jump Starting...............................................5-48
All-Wheel Drive..............................................5-54
Rear Axle.......................................................5-55
Four-Wheel Drive............................................5-56
Noise Control System.....................................5-58
Tampering with Noise Control System
Prohibited.................................................5-58
Section 5 Service and Appearance Care
5-1

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
B. Coolant Surge Tank. See
Engine Coolant on
page 5-30.
C. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-21.
D. Engine Oil Dipstick. See
Engine Oil on page 5-16.
E. Automatic Transmission Dipstick (If equipped).
See
Automatic Transmission Fluid (Except Allison
Transmissionž) on page 5-23orAutomatic
Transmission Fluid (Allison Transmissionž)on
page 5-26.
F. Fan. See
Cooling System on page 5-36.
G. Engine Oil Fill. See
Engine Oil on page 5-16.H. Power Steering Fluid Reservoir. See
Power Steering
Fluid on page 5-42.
I. Remote Negative (-) Terminal (GND). See
Jump
Starting on page 5-48.
J. Remote Positive (+) Terminal. See
Jump Starting on
page 5-48.
K. Brake Fluid Reservoir. See
Brakes on page 5-44.
L. Clutch Fluid Reservoir (If Equipped). See
Hydraulic
Clutch on page 5-29.
M. Underhood Fuse Block. See
Fuses and Circuit
Breakers on page 5-110.
N. Battery. See
Battery on page 5-47.
O. Windshield Washer Fluid Reservoir. See
Windshield
Washer Fluid on page 5-43.
5-11

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
B. Coolant Surge Tank. See
Engine Coolant on
page 5-30.
C. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-21.
D. Engine Oil Dipstick. See
Engine Oil on page 5-16.
E. Automatic Transmission Dipstick (If Equipped).
See
Automatic Transmission Fluid (Except Allison
Transmissionž) on page 5-23orAutomatic
Transmission Fluid (Allison Transmissionž)on
page 5-26.
F. Engine Oil Fill. See
Engine Oil on page 5-16.
G. Fan. See
Cooling System on page 5-36.H. Remote Negative (-) Terminal (GND). See
Jump
Starting on page 5-48.
I. Power Steering Fluid Reservoir. See
Power Steering
Fluid on page 5-42.
J. Remote Positive (+) Terminal. See
Jump Starting on
page 5-48.
K. Brake Fluid Reservoir. See
Brakes on page 5-44.
L. Clutch Fluid Reservoir (If Equipped). See
Hydraulic
Clutch on page 5-29.
M. Underhood Fuse Block. See
Fuses and Circuit
Breakers on page 5-110.
N. Battery. See
Battery on page 5-47.
O. Windshield Washer Fluid Reservoir. See
Windshield
Washer Fluid on page 5-43.
5-13

A. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-21.
B. Coolant Surge Tank. See
Engine Coolant on
page 5-30.
C. Air Filter Restriction Indicator (If Equipped). See
Engine Air Cleaner/Filter on page 5-21.
D. Engine Oil Dipstick. See
Engine Oil on page 5-16.
E. Automatic Transmission Dipstick (If Equipped).
See
Automatic Transmission Fluid (Except Allison
Transmissionž) on page 5-23orAutomatic
Transmission Fluid (Allison Transmissionž)on
page 5-26.
F. Engine Oil Fill. See
Engine Oil on page 5-16.
G. Fan. See
Cooling System on page 5-36.H. Remote Negative (-) Terminal (GND). See
Jump
Starting on page 5-48.
I. Remote Positive (+) Terminal. See
Jump Starting on
page 5-48.
J. Power Steering Fluid Reservoir. See
Power Steering
Fluid on page 5-42.
K. Brake Fluid Reservoir. See
Brakes on page 5-44.
L. Clutch Fluid Reservoir (If Equipped). See
Hydraulic
Clutch on page 5-29.
M. Underhood Fuse Block. See
Fuses and Circuit
Breakers on page 5-110.
N. Battery. See
Battery on page 5-47.
O. Windshield Washer Fluid Reservoir. See
Windshield
Washer Fluid on page 5-43.
5-15

When to Check and What to Use
The clutch master cylinder
reservoir is located in the
rear of the engine
compartment on the
driver's side of the vehicle.
See
Engine Compartment
Overview on page 5-10
for more information
on location.
Refer to the Maintenance Schedule to determine how
often you should check the ¯uid level in your clutch
master cylinder reservoir and for the proper ¯uid. See
Part B: Owner Checks and Services on page 6-12andPart D: Recommended Fluids and Lubricants on
page 6-19.
How to Check and Add Fluid
The proper ¯uid should be added if the level does not
reach the bottom of the diaphragm when it's in place in
the reservoir. See the instructions on the reservoir cap.
Engine Coolant
The cooling system in your vehicle is ®lled with
DEX-COOLžengine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs ®rst, if you add only
DEX-COOL
žextended life coolant.
The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating, see
Engine Overheating on
page 5-33.
A 50/50 mixture of clean, drinkable water and
DEX-COOL
žcoolant will:
·Give freezing protection down to-34ÉF (-37ÉC).
·Give boiling protection up to 265ÉF (129ÉC).
·Protect against rust and corrosion.
·Help keep the proper engine temperature.
·Let the warning lights and gages work as they
should.
5-30

Notice:When adding coolant, it is important that
you use only DEX-COOLž(silicate-free) coolant.
If coolant other than DEX-COOLžis added to
the system, premature engine, heater core or
radiator corrosion may result. In addition, the engine
coolant will require change sooner -- at 30,000 miles
(50,000 km) or 24 months, whichever occurs ®rst.
Damage caused by the use of coolant other
than DEX-COOL
žis not covered by your new vehicle
warranty.
What to Use
Use a mixture of one-halfclean, drinkable waterand
one-half DEX-COOLžcoolant which won't damage
aluminum parts. If you use this coolant mixture,
you don't need to add anything else.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can boil
before the proper coolant mixture will. Your
vehicle's coolant warning system is set for the
proper coolant mixture. With plain water or the
wrong mixture, your engine could get too hot
but you would not get the overheat warning.
Your engine could catch ®re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
žcoolant.
Notice:If you use an improper coolant mixture,
your engine could overheat and be badly damaged.
The repair cost wouldn't be covered by your
warranty. Too much water in the mixture can freeze
and crack the engine, radiator, heater core and
other parts.
If you have to add coolant more than four times a year,
have your dealer check your cooling system.
Notice:If you use the proper coolant, you don't
have to add extra inhibitors or additives which claim
to improve the system. These can be harmful.
5-31

Cooling System
When you decide it's safe to lift the hood, here's what
you'll see:
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Fan
If the coolant inside the coolant surge tank is boiling,
don't do anything else until it cools down. The vehicle
should be parked on a level surface. 8100 V8 Engines
All Other Engines
5-36