1998 BUICK CENTURY engine overheat

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6-21
Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant system. The thermostat stops the
flow of coolant through the radiator until the coolant
reaches a preset temperature.
When you replace your thermostat, a GM thermostat i
s recommended.
Engine Coolant
The cooling system in your vehicle is filled with
DEX
-COOL
engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX
-COOL
extended 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 ªEngine Overheatingº in
the Index.A 50/50 mixture of clean, drinkable water and
DEX
-COOL
coolant will:

Give freezing protection down to
-34F (-37C).

Give boiling protection up to 265F (129C).

Protect against rust and corrosion.

Help keep the proper engine temperature.

Let the warning lights and gages work as
they should.
NOTICE:
When adding coolant, it is important that you use
only DEX
-COOL (silicate-free) coolant.
If coolant other than DEX-COOL is 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 first. Damage caused by the use
of coolant other than DEX
-COOL is not
covered by your new vehicle warranty.

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6-22 What to Use
Use a mixture of one-half clean, drinkable water and
one
-half DEX-COOL
coolant 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 like 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 fire and you or others could be burned. Use
a 50/50 mixture of clean, drinkable water and
DEX
-COOL
coolant.
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.

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9-4
Driving
City 4-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Defensive 4-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drunken 4-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Freeway 4-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In a Blizzard 4-27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In the Rain 4-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Night 4-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On Curves 4-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On Grades While Towing a Trailer 4-37 . . . . . . . . . . . . . . .
On Hill and Mountain Roads 4-23 . . . . . . . . . . . . . . . . . . . .
On Snow and Ice 4-26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Through Water 4-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Wet Roads 4-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Winter 4-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
With a Trailer 4-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
DRL 2-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drunken Driving 4-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dual Automatic ComforTemp Climate Control 3-2 . . . . . . . . .
Electrical Equipment, Adding 3-19, 6-57 . . . . . . . . . . . . . . .
Electrical System 6-57 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrochromic Day/Night Rearview Mirror 2-46 . . . . . . . . . .
With Compass 2-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electronic Level Control 4-32 . . . . . . . . . . . . . . . . . . . . . . . . .
Engine 6-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Accessory Belt 6-68 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air Cleaner/Filter 6-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant 6-21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Heater 2-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Level Check 7-31 . . . . . . . . . . . . . . . . . . . . . . . . . . Coolant Temperature Gage 2
-73 . . . . . . . . . . . . . . . . . . . . .
Coolant Temperature Warning Light 2-72 . . . . . . . . . . . . . .
Exhaust 2-32, 4-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fuse Block 6-60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Identification 6-56 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Level Check 7-31 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overheating 5-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Running While Parked 2-32 . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 6-67 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting Your 2-21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Supercharged 6-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Oil 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding 6-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additives 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking 6-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pressure Light 2-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Used 6-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When to Change 6-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust, Engine 2-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exit Lighting, Delayed 2-43 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Express-Down Window 2-34 . . . . . . . . . . . . . . . . . . . . . . . . . .
Fabric Cleaning 6
-48 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fan Button, Climate Control System 3-3 . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter, Air 6-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Care 6-52 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Damage 6-54 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flashers, Hazard Warning 5-2 . . . . . . . . . . . . . . . . . . . . . . . . .
Flash-To-Pass Feature 2-36 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Flat Tire, Changing 5-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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9-7
Memory Door 2-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Door 2-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Trunk 2-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low Coolant Warning Light 2-73 . . . . . . . . . . . . . . . . . . . . . .
Low Fuel Light 2-79 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lubricants and Fluids 7-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lubrication Service, Body 7-32 . . . . . . . . . . . . . . . . . . . . . . . .
Lumbar Controls 1-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Magnasteer
4-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance, Normal Replacement Parts 6-67 . . . . . . . . . . . .
Maintenance Record 7-38 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance Schedule 7-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Long Trip/Highway Definition 7-6 . . . . . . . . . . . . . . . . . . .
Long Trip/Highway Intervals 7-6 . . . . . . . . . . . . . . . . . . . . .
Owner Checks and Services 7-31 . . . . . . . . . . . . . . . . . . . . .
Periodic Maintenance Inspections 7-35 . . . . . . . . . . . . . . . .
Recommended Fluids and Lubricants 7-36 . . . . . . . . . . . . .
Short Trip/City Definition 7-5 . . . . . . . . . . . . . . . . . . . . . . .
Short Trip/City Intervals 7-5 . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance, Underbody 6-54 . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance When Trailer Towing 4-38 . . . . . . . . . . . . . . . . .
Malfunction Indicator Lamp 2-74 . . . . . . . . . . . . . . . . . . . . . .
Memory
Door Locks 2
-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Seats and Mirrors 1-3, 1-4, 2-10 . . . . . . . . . . . . . . . . . . . . .
Mirrors 2-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic Dimming Outside Rearview 2-51 . . . . . . . . . . . .
Convex Outside 2-51 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrochromic Day/Night Rearview 2-46 . . . . . . . . . . . . . .
Heated Outside Rearview 2-51 . . . . . . . . . . . . . . . . . . . . . . . Inside Day/Night Rearview 2
-46 . . . . . . . . . . . . . . . . . . . . .
Memory 1-3, 1-4, 2-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parallel Park Assist 2-50 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Remote Control 2-50 . . . . . . . . . . . . . . . . . . . . . . . . .
Visor Vanity 2-58 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
With Compass 2-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mountain Roads 4-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multifunction Lever 2-35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Net, Convenience 2-57 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
New Vehicle Break-In 2-18 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Night Vision 4-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Normal Maintenance Replacement Parts 6-67 . . . . . . . . . . . . .
Odometer 2-67 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Odometer, Trip 2-67 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Off-Road Recovery 4-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil, Engine 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Pressure Light 2-77 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil, Supercharger 6-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OnStar
System 2-58 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Opener, Garage Door 2-52, 2-60 . . . . . . . . . . . . . . . . . . . . . . .
Outside Rearview Mirrors 2-46 . . . . . . . . . . . . . . . . . . . . . . . .
Overheating Engine 5-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Owner Checks and Services 7-31 . . . . . . . . . . . . . . . . . . . . . . .
Owner Publications, Ordering 8-11 . . . . . . . . . . . . . . . . . . . . .
Paint Spotting, Chemical 6-54 . . . . . . . . . . . . . . . . . . . . . . . .
Parade Dimming 2-43 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parallel Park Assist Mirror 2-50 . . . . . . . . . . . . . . . . . . . . . . . .