2003 BUICK CENTURY engine overheat

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

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

E
Electrical System............................................5-88
Add-On Equipment......................................5-88
Fuses and Circuit Breakers...........................5-89
Headlamp Wiring.........................................5-88
Power Windows and Other Power Options......5-88
Windshield Wiper Fuses...............................5-88
Emergency Trunk Release Handle.....................2-14
Emissions Inspection and Maintenance
Programs...................................................3-33
Engine Coolant Level Check.............................6-10
Engine Cooling When Trailer Towing..................4-41
Engine Oil Additives........................................5-16
Engine Oil Level Check...................................6-10
Engine Oil Scheduled Maintenance..................... 6-5
Engine..........................................................5-18
Air Cleaner/Filter.........................................5-18
Battery.......................................................5-42
Change Engine Oil Light...............................3-35
Check and Service Engine Soon Light............3-31
Compartment Overview................................5-12
Coolant Heater............................................2-21
Coolant Temperature Gage...........................3-30
Coolant Temperature Warning Light................3-29
Coolant......................................................5-23
Cooling System Inspection............................6-14Engine (cont.)
Exhaust.....................................................2-30
Oil .............................................................5-13
Overheating................................................5-26
Starting......................................................2-20
Enhanced Traction System (ETS)......................4-10
Warning Light.............................................3-28
Entry Lighting.................................................3-14
Express-Down Window....................................2-16
Extender, Safety Belt.......................................1-29
Exterior Lamps...............................................3-11
F
Filter.............................................................5-18
Engine Air Cleaner......................................5-18
Finding a Station....................................3-40, 3-42
Finish Care....................................................5-83
Finish Damage...............................................5-84
Fixed Mast Antenna........................................3-52
Flash-to-Pass................................................... 3-7
Flat Tire, Changing.........................................5-67
Flat Tire........................................................5-66
Fluid.............................................................5-19
Automatic Transaxle.....................................5-19
Power Steering...........................................5-36
Windshield Washer......................................5-38
5

Other Warning Devices...................................... 3-4
Outlet Adjustment............................................3-20
Outside.........................................................2-33
Convex Mirror.............................................2-33
Power Mirrors.............................................2-33
Overheated Engine Protection Operating Mode . . . 5-26
Overseas ± Customer Assistance........................ 7-5
Owners, Canadian............................................... ii
Owner's Information........................................7-12
P
Park (P)........................................................2-29
Shifting Out of............................................2-29
Parking Brake and Automatic Transaxle Park (P)
Mechanism Check.......................................6-13
Parking on Hills..............................................4-40
Parking.........................................................2-26
Brake........................................................2-26
Over Things That Burn.................................2-29
Park(P).........................................................2-26
Shifting Into................................................2-26Part A - Scheduled Maintenance Services............ 6-4
Part B - Owner Checks and Services................6-10
Part C - Periodic MaintenanceInspections..........6-14
Part D - Recommended Fluids and Lubricants....6-16
Part E - Maintenance Record...........................6-17
Passenger Compartment Air Filter.....................3-20
Passing.................................................4-14, 4-39
PASS-Key
žII .................................................2-17
Plan Ahead When Possible................................ 7-8
Playing a Cassette Tape..................................3-44
Playing a Compact Disc...................................3-46
Playing the Radio...................................3-40, 3-42
Power Steering...............................................4-11
Power...........................................................3-16
Auxiliary Connection.....................................3-16
Door Locks.................................................2-11
Drop..........................................................3-16
Electrical System.........................................5-88
Six-Way Seats.............................................. 1-3
Steering Fluid.............................................5-36
Windows....................................................2-16
Programmable Automatic Door Locks.................2-11
10