2003 CHEVROLET SILVERADO Cooling system

The coolant level should
be at or above the FULL
COLD mark. If it isn't,
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.
{CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Do not touch them. If
you do, you can be burned.
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 ®re, and you could be
burned. Get any leak ®xed before you drive the
vehicle.If there seems to be no leak, start the engine again.
The engine cooling fan speed should increase when idle
speed is doubled by pushing the accelerator pedal
down. If it doesn't, your vehicle needs service. Turn off
the engine.
Notice:Engine damage from running your engine
without coolant isn't covered by your warranty.
See ªOverheated Engine Protection Operating
Modeº in the Index for information on driving to a
safe place in an emergency.
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 Ð 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.
5-37

How to Add Coolant to the Coolant
Surge Tank Gasoline Engines
If you haven't found a problem yet, check to see if coolant
is visible in the surge tank. If coolant is visible but the
coolant level isn't at or above the FULL COLD mark, add
a 50/50 mixture of
clean, drinkable waterand
DEX-COOLžcoolant at the coolant surge tank, but be
sure the cooling system, including the coolant surge tank
pressure cap, is cool before you do it. See
Engine
Coolant on page 5-30for more information.
If no coolant is visible in the surge tank, add coolant as
follows:
{CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the coolant
surge tank pressure cap Ð even a little Ð they
can come out at high speed. Never turn the
cap when the cooling system, including the
coolant surge tank pressure cap, is hot. Wait
for the cooling system and coolant surge tank
pressure cap to cool if you ever have to turn
the pressure cap.{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
CAUTION: (Continued)
5-38

CAUTION: (Continued)
proper coolant mixture. With plain water or the
wrong mixture, your engine could get too hot
but you wouldn't 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 a proper coolant.
Notice:In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
{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.1. Park the vehicle on a
level surface. You can
remove the coolant
surge tank pressure
cap when the cooling
system, including
the coolant surge tank
pressure cap and
upper radiator hose, is
no longer hot.
2. Turn the pressure cap slowly counterclockwise (left)
about one full turn. If you hear a hiss, wait for that to
stop. A hiss means there is still some pressure left.
3. Then keep turning the pressure cap slowly, and
remove it.
5-39

6. Then replace the
pressure cap. Be sure
the pressure cap is
hand-tight and
fully seated.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
disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
5-41

ApplicationCapacities
English Metric
Cooling System
After re®ll, the level must be rechecked. See ªCooling Systemº in the Index.
VORTECŸ 4300 V6 Automatic Transmission 12.6 quarts (11.9 L)
VORTECŸ 4300 V6 Manual Transmission 12.9 quarts (12.2 L)
VORTECŸ 4800 V8 Automatic Transmission 13.4 quarts (12.7 L)
VORTECŸ 4800 V8 Manual Transmission 13.7 quarts (13.0 L)
VORTECŸ 5300 V8 Automatic Transmission 13.4 quarts (12.7 L)
VORTECŸ 5300 V8** Automatic Transmission 14.9 quarts (14.1 L)
VORTECŸ 6000 V8 Automatic Transmission 14.8 quarts (14.0 L)
VORTECŸ 6000 V8* Automatic Transmission 14.4 quarts (13.6 L)
VORTECŸ 6000 V8 Manual Transmission 15.2 quarts (14.4 L)
VORTECŸ 6000 V8* Manual Transmission 14.8 quarts (14.0 L)
VORTECŸ 8100 V8 Manual Transmission 21.1 quarts (20.0 L)
VORTECŸ 8100 V8 Automatic Transmission 20.7 quarts (19.6 L)
* Vehicles equipped with the optional engine oil cooler.
** Vehicles equipped with the optional air conditioner.
Engine Oil With Filter
After re®ll, the level must be rechecked. Add enough engine oil so that the ¯uid is within the proper operating
range. See
Engine Oil on page 5-16.
VORTECŸ 4300 V6 (Vin W) 4.5 quarts (4.3 L)
VORTECŸ 4800 V8 ( Vin V) 6.0 quarts (5.7 L)
VORTECŸ 5300 V8 (Vin T) 6.0 quarts (5.7 L)
VORTECŸ 6000 V8 (Vin U) 6.0 quarts (5.7 L)
5-119

Maintenance Schedule......................................6-2
Introduction...................................................6-2
Your Vehicle and the Environment....................6-2
Maintenance Requirements..............................6-2
How This Section is Organized.........................6-3
Part A: Scheduled Maintenance Services...........6-4
Using Your Maintenance Schedule....................6-4
Scheduled Maintenance...................................6-5
Part B: Owner Checks and Services................6-12
At the First 100, 1,000 and 6,000 Miles
(160, 1 600 and 10 000km)........................6-12
At Each Fuel Fill..........................................6-12
At Least Once a Month.................................6-12
At Least Twice a Year...................................6-13
At Least Once a Year...................................6-14Part C: Periodic MaintenanceInspections.........6-17
Steering and Suspension Inspection................6-17
Exhaust System Inspection............................6-17
Fuel System Inspection..................................6-17
Engine Cooling System Inspection...................6-17
Throttle System Inspection
(V6 Only).................................................6-18
Transfer Case and Front Axle (All-Wheel
Drive) Inspection.......................................6-18
Transfer Case and Front Axle (Four-Wheel
Drive) Inspection.......................................6-18
Brake System Inspection................................6-18
Part D: Recommended Fluids and Lubricants. . . .6-19
Part E: Maintenance Record...........................6-22
Section 6 Maintenance Schedule
6-1

100,000 Miles (166 000 km)
qInspect spark plug wires.An Emission Control
Service.
qReplace spark plugs.An Emission Control Service.
qChange automatic transmission ¯uid and ®lter if
the vehicle's GVWR is over 8600 lbs, if the
vehicle has an Allison transmission or if the vehicle is
mainly driven under one or more of these conditions:
þ In heavy city traffic where the outside
temperature regularly reaches 90ÉF (32ÉC) or
higher.
þ In hilly or mountainous terrain.
þ When doing frequent trailer towing.
þ Uses such as found in taxi, police or delivery
service.
qIf you haven't used your vehicle under severe service
conditions listed previously and, therefore, haven't
changed your automatic transmission ¯uid, change
both the ¯uid and ®lterqAutomatic Transfer Case Only: Change transfer case
¯uid
qExcept 8.1L V8 Engine: Inspect Positive Crankcase
Ventilation (PCV) valve.
An Emission Control
Service.
150,000 Miles (240 000 km)
qDrain, ¯ush and re®ll cooling system (or every
60 months since last service, whichever occurs ®rst).
See
Engine Coolant on page 5-30for what to use.
Inspect hoses. Clean radiator, condenser, pressure
cap and neck. Pressure test the cooling system
and pressure cap.
An Emission Control Service.
qChange ®ve-speed manual transmission ¯uid (with
4300 V6 or 4800 V8 engines only).
qInspect engine accessory drive belt.
An Emission
Control Service.
200,000 Miles (332 000 km)
q6000 V8 Engine Only: Change ®ve-speed manual
transmission ¯uid.
6-11

Part C: Periodic
MaintenanceInspections
Listed in this part are inspections and services which
should be performed at least twice a year (for instance,
each spring and fall).
You should let your dealer's
service department do these jobs. Make sure any
necessary repairs are completed at once.
Proper procedures to perform these services may be
found in a service manual. SeeService Publications
Ordering Information on page 7-9.
Steering and Suspension Inspection
Inspect the front and rear suspension and steering
system for damaged, loose or missing parts, signs of
wear or lack of lubrication. Inspect the power steering
lines and hoses for proper hook-up, binding, leaks,
cracks, cha®ng, etc.
Exhaust System Inspection
Inspect the complete exhaust system. Inspect the body
near the exhaust system. Look for broken, damaged,
missing or out-of-position parts as well as open seams,
holes, loose connections or other conditions which
could cause a heat build-up in the ¯oor pan or could let
exhaust fumes into the vehicle. See
Engine Exhaust
on page 2-51.
Fuel System Inspection
Inspect the complete fuel system for damage or leaks.
Engine Cooling System Inspection
Inspect the hoses and have them replaced if they
are cracked, swollen or deteriorated. Inspect all pipes,
®ttings and clamps; replace as needed. Clean the
outside of the radiator and air conditioning condenser.
To help ensure proper operation, a pressure test of
the cooling system and pressure cap is recommended
at least once a year.
6-17