1999 BUICK CENTURY light

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6-11
Before closing the hood, be sure all the filler caps are
on properly. Then just pull the hood down and close
it firmly.
Engine Oil
If the LOW OIL light on the
instrument panel comes on,
it means you need to check
your engine oil level
right away.
For more information, see ªLow Oil Level Lightº in the
Index. You should check your engine oil level regularly;
this is an added reminder.
It's a good idea to check your engine oil every time you
get fuel. In order to get an accurate reading, the oil must
be warm and the vehicle must be on level ground.
The engine oil dipstick handle is the yellow loop near
the front of the engine.
Turn off the engine and give the oil several minutes to
drain back into the oil pan. If you don't, the oil dipstick
might not show the actual level.

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6-15 Engine Oil Additives
Don't add anything to your oil. Your dealer is ready to
advise if you think something should be added.
When to Change Engine Oil
Your vehicle has a computer that lets you know when to
change your engine oil. This is not based on mileage,
but on engine revolutions and engine operating
temperature. When the computer has calculated that the
oil needs changing, the Oil Life Monitor will indicate
that a change is necessary. The mileage between oil
changes will vary depending on how you drive your
vehicle
-- usually between 3,000 miles (5 000 km) and
7,500 miles (12 500 km) since your last oil change.
Under severe conditions, the indicator may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 7,500 miles (12 500 km) or 12 months
(whichever occurs first) without an oil change.
The system won't detect dust in the oil. So, if you
drive in a dusty area, be sure to change your oil every
3,000 miles (5 000 km) or sooner. Remember to
reset the CHANGE OIL SOON light whenever the oil
is changed.How to Reset the Oil Life Monitor
After changing the engine oil, the system must be reset.
With the ignition key in RUN but the engine off, fully
push and release the accelerator pedal slowly three times
within five seconds. If the CHANGE OIL SOON light
flashes, the system is resetting. Turn the key to OFF,
then start the vehicle. If the CHANGE OIL SOON
light comes back on, the system has not reset. Repeat
the procedure.
What to Do with Used Oil
Did you know that used engine oil contains certain
elements that may be unhealthy for your skin and could
even cause cancer? Don't let used oil stay on your skin
for very long. Clean your skin and nails with soap and
water, or a good hand cleaner. Wash or properly throw
away clothing or rags containing used engine oil. (See
the manufacturer's warnings about the use and disposal
of oil products.)
Used oil can be a real threat to the environment. If you
change your own oil, be sure to drain all free
-flowing oil
from the filter before disposal. Don't ever dispose of oil
by putting it in the trash, pouring it on the ground, into
sewers, or into streams or bodies of water. Instead,
recycle it by taking it to a place that collects used oil. If
you have a problem properly disposing of your used oil,
ask your dealer, a service station or a local recycling
center for help.

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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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6-23
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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6-27
Brakes
Brake Fluid
Your brake master cylinder reservoir is on the driver's
side of the engine compartment. It is filled with DOT
-3
brake fluid.
There are only two reasons why the brake fluid level in the
reservoir might go down. The first is that the brake fluid
goes down to an acceptable level during normal brake
lining wear. When new linings are put in, the fluid level
goes back up. The other reason is that fluid is leaking outof the brake system. If it is, you should have your brake
system fixed, since a leak means that sooner or later your
brakes won't work well, or won't work at all.
So, it isn't a good idea to ªtop offº your brake fluid.
Adding brake fluid won't correct a leak. If you add fluid
when your linings are worn, then you'll have too much
fluid when you get new brake linings. You should add
(or remove) brake fluid, as necessary, only when work is
done on the brake hydraulic system.
CAUTION:
If you have too much brake fluid, it can spill on
the engine. The fluid will burn if the engine is
hot enough. You or others could be burned,
and your vehicle could be damaged. Add brake
fluid only when work is done on the brake
hydraulic system.
When your brake fluid falls to a low level, your brake
warning light will come on. See ªBrake System Warning
Lightº in the Index.

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6-29 Brake Wear
Your vehicle has front disc brakes and rear drum brakes.
Disc brake pads have built
-in wear indicators that make
a high
-pitched warning sound when the brake pads
are worn and new pads are needed. The sound may
come and go or be heard all the time your vehicle is
moving (except when you are pushing on the brake
pedal firmly).
CAUTION:
The brake wear warning sound means that soon
your brakes won't work well. That could lead to
an accident. When you hear the brake wear
warning sound, have your vehicle serviced.
NOTICE:
Continuing to drive with worn-out brake pads
could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly torque wheel nuts in the
proper sequence to GM specifications.
Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7 of this
manual under Part C ªPeriodic Maintenance
Inspections.º
Brake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in pedal
travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you apply the brakes, with or without the
vehicle moving, your brakes adjust for wear.

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6-42 Low Tire Inflation Monitor System
(If Equipped)
The low tire inflation monitor system can alert you to a
large change in the pressure of one tire. The system
ªlearnsº the pressure at each tire throughout the
operating speed range of your vehicle. The system
normally takes between 45 and 90 minutes of driving to
learn the tire pressures. This time may be longer
depending on your individual driving habits. Learning
need not be accumulated during a single trip. Once
learned, the system will remember the tire pressures
until the system is recalibrated.
After the system has learned tire pressures with properly
inflated tires, the LOW TIRE light will come on if the
pressure in one tire becomes 12 psi (83 kPa) lower than
the other three tires. The low tire inflation monitor
system won't alert you if the pressure in more than one
tire is low, if the system is not properly calibrated, or if
the vehicle is moving faster than 60 mph (95 km/h).
The low tire inflation monitor system detects differences
in tire rotation speeds that are caused by changes in
tire pressure. The system can alert you about a low
tire
-- but it doesn't replace normal tire maintenance.
See ªTiresº in the Index.When the LOW TIRE light comes on, you should stop
as soon as you can and check all your tires for damage.
(If a tire is flat, see ªIf a Tire Goes Flatº in the Index.)
Also check the tire pressure in all four tires as soon as
you can. See ªInflation
- Tire Pressureº in the Index.
The light will come on and stay on until you turn off the
ignition or press the RESET button.
Don't reset the low tire inflation monitor system without
first correcting the cause of the problem and checking
and adjusting the pressure in all four tires. If you reset
the system when the tire pressures are incorrect, the
system will not work properly and may not alert you
when a tire is low.
Any time you adjust a tire's pressure, rotate your tires,
or have one or more tires repaired or replaced, you'll
need to reset (calibrate) the low tire inflation monitor
system. You'll also need to reset the system whenever
you buy new tires and whenever the vehicle's battery
has been disconnected.
To reset (calibrate) the system: turn the ignition switch
to RUN. Then press and hold the RESET button for
about five seconds.

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6-43
The red RESET
button is located inside
your instrument panel
fuse block.
The fuse block is located under the cover labeled
FUSES, which is at the end of the instrument panel on
the passenger's side of the vehicle. The RESET button is
the first button in the top row of the fuse block. The
LOW TIRE light will come on and flash three times.
Then it will go off. If the light doesn't go off, see your
dealer for service.
The system completes the calibration process
during driving.The system normally takes 15 to 20 minutes of driving
in each of three speed ranges to ªlearnº tire pressures.
The speed ranges are 15 to 40 mph (25 to 65 km/h),
40 to 65 mph (65 to 105 km/h) and above 65 mph
(105 km/h). When learning is complete, the system will
alert you after 2
-8 minutes if a tire is 12 psi (83 kPa)
different from the other three tires. Detection thresholds
may be higher and detection times may be longer on
rough roads, curves and at high speeds. The system
is not capable of detection at speeds greater than
60 mph (95 km/h).
Tire Inspection and Rotation
Tires should be rotated every 6,000 to 8,000 miles
(10 000 to 13 000 km). Any time you notice unusual
wear, rotate your tires as soon as possible and check
wheel alignment. Also check for damaged tires or
wheels. See ªWhen It's Time for New Tiresº and
ªWheel Replacementº later in this section for
more information.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The first
rotation is the most important. See ªScheduled
Maintenance Servicesº in the Index for scheduled
rotation intervals.