2003 BUICK CENTURY radiator

When the engine is cold,
the coolant level should be
at or above the COLD
mark on the coolant
recovery tank. 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. Don't touch them. If you
do, you can be burned.
Don't 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, with the engine on, check
to see if the electric engine cooling fans are running.
If the engine is overheating, both fans should be
running. If they aren't, your vehicle needs service.
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.
5-30

How to Add Coolant to the Coolant
Recovery Tank
If you haven't found a problem yet, but the coolant level
isn't at the COLD mark, add a 50/50 mixture ofclean,
drinkable waterand DEX-COOLžengine coolant at
the coolant recovery tank. SeeEngine Coolant on
page 5-23for more information.
{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
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 DEX-COOL
žcoolant.
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. Don't spill coolant on a hot engine.
When the coolant in the coolant recovery tank is at the
COLD mark, start your vehicle.
5-31

If the overheat warning continues, there's one more
thing you can try. You can add the proper coolant
mixture directly to the radiator, but be sure the cooling
system is cool before you do it.
{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 radiator
pressure cap Ð even a little Ð they can come
out at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap, is hot. Wait for the cooling system and
radiator pressure cap to cool if you ever have
to turn the pressure cap.
5-32

How to Add Coolant to the Radiator
Notice:Your engine has a speci®c radiator
®ll procedure. Failure to follow this procedure could
cause your engine to overheat and be severely
damaged.
1. You can remove the radiator pressure cap when
the cooling system, including the radiator pressure
cap and upper radiator hose, is no longer hot.
Turn the pressure cap slowly counterclockwise until
it ®rst stops. (Don't press down while turning the
pressure cap.)If you hear a hiss, wait for that to stop. A hiss
means there is still some pressure left.
2. Then keep turning the pressure cap, but now push
down as you turn it. Remove the pressure cap.
5-33

{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. Don't spill coolant on a hot engine.
3. After the engine cools, open the coolant air bleed
valves.
There are two bleed valves. One is located on the
thermostat housing. The other is located on the
thermostat bypass tube.4. Fill the radiator with the
proper DEX-COOL
ž
coolant mixture,
up to the base of the
®ller neck. See
Engine Coolant on
page 5-23for more
information about the
proper coolant mixture.
If you see a stream of coolant coming from an air
bleed valve, close the valve. Otherwise, close
the valves after the radiator is ®lled.
5. Rinse or wipe any spilled coolant from the engine
and the compartment.
5-34

6. Then ®ll the coolant recovery tank to the COLD
mark on the coolant recovery tank.
7. Put the cap back on the coolant recovery tank, but
leave the radiator pressure cap off.8. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fans.
9. By this time, the coolant level inside the radiator
®ller neck may be lower. If the level is lower, add
more of the proper DEX-COOL
žcoolant mixture
through the ®ller neck until the level reaches
the base of the ®ller neck.
5-35

90,000 Miles (150 000 km)
qReplace passenger compartment air ®lter. If you
drive regularly under dusty conditions, the ®lter
may require replacement more often.
qReplace engine air cleaner ®lter. See
Engine Air
Cleaner/Filter on page 5-18for more information.An Emission Control Service.
qRotate tires. SeeTire Inspection and Rotation on
page 5-60for proper rotation pattern and additional
information.(See footnote .) (See footnote +.)
97,500 Miles (162 500 km)
qRotate tires. SeeTire Inspection and Rotation on
page 5-60for proper rotation pattern and additional
information.(See footnote .) (See footnote +.)
100,000 Miles (166 000 km)
qInspect spark plug wires.An Emission Control
Service.
qReplace spark plugs.An Emission Control Service.
qChange automatic transaxle ¯uid and ®lter 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 transaxle ¯uid, change both
the ¯uid and ®lter.
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 5-23for what to use.
Inspect hoses. Clean radiator, condenser, pressure
cap and neck. Pressure test the cooling system
and pressure cap.
An Emission Control Service.
qInspect engine accessory drive belt.An Emission
Control Service.
6-9

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 7-11.
Steering, Suspension and Front
Drive Axle Boot and Seal 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. Clean and then inspect the drive
axle boot seals for damage, tears or leakage. Replace
seals if necessary.
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 2-30.
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.
6-14