1999 BUICK CENTURY engine overheat

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5-33
If You're Stuck: In Sand, Mud,
Ice or Snow
In order to free your vehicle when it is stuck, you will
need to spin the wheels, but you don't want to spin your
wheels too fast. The method known as ªrockingº can
help you get out when you're stuck, but you must
use caution.
CAUTION:
If you let your tires spin at high speed, they can
explode, and you or others could be injured. And,
the transaxle or other parts of the vehicle can
overheat. That could cause an engine
compartment fire or other damage. When you're
stuck, spin the wheels as little as possible. Don't
spin the wheels above 35 mph (55 km/h) as shown
on the speedometer.
NOTICE:
Spinning your wheels can destroy parts of your
vehicle as well as the tires. If you spin the wheels
too fast while shifting your transaxle back and
forth, you can destroy your transaxle.
For information about using tire chains on your vehicle,
see ªTire Chainsº in the Index.
Rocking Your Vehicle To Get It Out
First, turn your steering wheel left and right. That will
clear the area around your front wheels. You should turn
the Enhanced Traction System off. (See ªEnhanced
Traction Systemº in the Index. Then shift back and forth
between REVERSE (R) and a forward gear, spinning the
wheels as little as possible. REVERSE (R) and FIRST (1)
or SECOND (2) gear. The Enhanced Traction System will
be turned off in FIRST (1) or SECOND (2) gear. Spin the
wheels as little as possible. Release the accelerator pedal
while you shift, and press lightly on the accelerator pedal
when the transaxle is in gear. By slowly spinning your
wheels in the forward and reverse directions, you will
cause a rocking motion that may free your vehicle. If that
doesn't get you out after a few tries, you may need to be
towed out. If you do need to be towed out, see ªTowing
Your Vehicleº in the Index.

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6-21
Radiator Pressure Cap
NOTICE:
Your radiator cap is a 15 psi (105 kPa)
pressure
-type cap and must be tightly installed to
prevent coolant loss and possible engine damage
from overheating. Be sure the arrows on the cap
line up with the overflow tube on the radiator
filler neck.
When you replace your radiator pressure cap, an
ACDelco
cap is recommended.
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, an ACDelco


thermostat is 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 or if you need to add coolant to your
radiator, 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.

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6-22
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.
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.

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6-23
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.
Checking Coolant
The vehicle must be on a
level surface. When your
engine is cold, the coolant
level should be at the
COLD mark or a little
higher. When your engine is
warm, the level should be
up to the HOT mark or a
little higher.
If this LOW COOLANT
light comes on and stays on,
it means you're low on
engine coolant.

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6-24
Adding Coolant
If you need more coolant, add the proper DEX
-COOL

coolant mixture at the coolant recovery tank, but be
careful not to spill it.
If the coolant recovery tank is completely empty, add
coolant to the radiator. (See ªEngine Overheatingº in
the Index.)
CAUTION:
Turning the radiator pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. With the coolant recovery tank, you will
almost never have to add coolant at the radiator.
Never turn the radiator pressure cap
-- even a
little
-- when the engine and radiator are hot.
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.
Power Steering Fluid

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9-4
Driving
City 4-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Defensive 4-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drunken 4-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Freeway 4-21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In a Blizzard 4-27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
In Foreign Countries 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . .
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 or Ice 4-26 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Through Deep Standing Water 4-19 . . . . . . . . . . . . . . . . . . .
Wet Roads 4-17 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Winter 4-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
With a Trailer 4-35 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Drunken Driving 4-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Dual Automatic ComforTemp Climate Control 3-7 . . . . . . . . .
Dual ComforTemp Climate Control 3-4 . . . . . . . . . . . . . . . . . .
Electrical Equipment, Adding 2-19, 2-46, 3-30, 6-58 . . . . .
Electrical System 6-58 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrochromic Day/Night Rearview Mirror 2-43 . . . . . . . . . .
Engine 6-10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant 6-21 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Heater 2-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Level Check 7-14 . . . . . . . . . . . . . . . . . . . . . . . . . .
Coolant Temperature Gage 2-56 . . . . . . . . . . . . . . . . . . . . .
Coolant Temperature Light 2-55 . . . . . . . . . . . . . . . . . . . . .
Exhaust 2-30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Identification 6
-58 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Level Check 7-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overheating 5-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Running While Parked 2-30 . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 6-64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting Your V6 2-18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Air Cleaner/Filter 6-16 . . . . . . . . . . . . . . . . . . . . . . . . .
Engine Oil 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adding 6-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Additives 6-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking 6-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Monitor 6-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Used 6-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
What Kind to Use 6-13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
When to Change 6-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Enhanced Traction System 4-9 . . . . . . . . . . . . . . . . . . . . . . . . .
Active Light 2-54 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Warning Light 2-53 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ethanol 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exhaust, Engine 2-30 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Exterior Lamps 2-38 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fabric Cleaning 6-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filling Your Tank 6-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter, Engine Air Cleaner/ 6-16 . . . . . . . . . . . . . . . . . . . . . . . .
Filter, Engine Oil 6-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Filter, Passenger Compartment Air 6-17 . . . . . . . . . . . . . . . . .
Finish Care 6-54 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Finish Damage 6-56 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
First Gear, Automatic Transaxle 2-24 . . . . . . . . . . . . . . . . . . .
Flashers, Hazard Warning 5-2 . . . . . . . . . . . . . . . . . . . . . . . . .

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9-7
Rear-Door Child Security 2-6 . . . . . . . . . . . . . . . . . . . . . . .
Trunk 2-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Window 2-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Loss of Control 4-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low
Coolant Warning Light 2
-56, 6-23 . . . . . . . . . . . . . . . . . . . .
Fuel Light 2-64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Level Light 2-61, 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . .
Tire Light 2-57 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Traction Light 2-55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Washer Fluid Warning Light 2-35, 2-63 . . . . . . . . . . . . . . .
Low-Beam Headlamps 2-34 . . . . . . . . . . . . . . . . . . . . . . . . . .
Lubricants and Fluids 7-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Lubrication Service, Body 7-15 . . . . . . . . . . . . . . . . . . . . . . . .
Magnetic Variable Effort Steering4-10 . . . . . . . . . . . . . . .
Maintenance, Normal Replacement Parts 6-65 . . . . . . . . . . . .
Maintenance Record 7-21 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance Schedule 7-1, 7-5 . . . . . . . . . . . . . . . . . . . . . . . .
How it's Organized 7-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Introduction 7-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Owner Checks and Services 7-14 . . . . . . . . . . . . . . . . . . . . .
Recommended Fluids and Lubricants 7-20 . . . . . . . . . . . . .
Periodic Maintenance Inspections 7-18 . . . . . . . . . . . . . . . .
Scheduled Maintenance Services 7-4 . . . . . . . . . . . . . . . . . .
Your Vehicle and the Environment 7-2 . . . . . . . . . . . . . . . .
Maintenance, Underbody 6-56 . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance When Trailer Towing 4-38 . . . . . . . . . . . . . . . . .
Malfunction Indicator Lamp 2-58 . . . . . . . . . . . . . . . . . . . . . .
Manual
Door Locks 2
-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front Seat 1-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Manual Single Zone Climate Control 3
-2 . . . . . . . . . . . . . . . .
Methanol 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mirrors 2-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Automatic Dimming/Heated Outside Rearview 2-44 . . . . .
Convex Outside 2-44 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Electrochromic Day/Night Rearview 2-43 . . . . . . . . . . . . . .
Power Outside Foldaway 2-43 . . . . . . . . . . . . . . . . . . . . . . .
Visor Vanity 2-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
MMT 6-4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mountain Roads 4-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Multifunction Lever 2-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Net, Trunk Convenience 2-45 . . . . . . . . . . . . . . . . . . . . . . . .
Neutral, Automatic Transaxle 2-22 . . . . . . . . . . . . . . . . . . . . .
New Vehicle ªBreak-Inº 2-16 . . . . . . . . . . . . . . . . . . . . . . . . .
Night Vision 4-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Odometer 2-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Odometer, Trip 2-50 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Offices, Customer Assistance 8-4 . . . . . . . . . . . . . . . . . . . . . .
Off-Road Recovery 4-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil, Engine 6-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Oil Warning Light 2-60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OnStar
2-47 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Overdrive, (
) Automatic 2-23 . . . . . . . . . . . . . . . . . . . . . . . .
Overheated Engine Protection Operating Mode 5-9 . . . . . . . .
Overheating Engine 5-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .