2002 BUICK CENTURY service

6-18
7. Remove the passenger compartment air filter.
8. Then replace the old air filter with the new one. For
the type of filter to use, see ªNormal Maintenance
Replacement Partsº in the Index.
9. Reinstall the air inlet grille.
10. Reinstall the air inlet grille retainers.
11. Reattach the hood weatherstrip.
12. Reconnect the windshield washer pump hose to the
fender rail and air inlet grille.
13. Close the hood.
14. Return the windshield wipers to the park position.
Automatic Transaxle Fluid
When to Check and Change
A good time to check your automatic transaxle fluid
level is when the engine oil is changed.
Change both the fluid and filter every 50,000 miles
(83 000 km) if the vehicle is mainly driven under one or
more of these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90F (32C) or higher.

In hilly or mountainous terrain.

When doing frequent trailer towing.

Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of
these conditions, change the fluid and filter at
100,000 miles (166 000 km).
See ªScheduled Maintenance Servicesº in the Index.

6-19 How to Check
Because this operation can be a little difficult,
you may choose to have this done at the dealership
service department.
If you do it yourself, be sure to follow all the instructions
here, or you could get a false reading on the dipstick.
NOTICE:
Too much or too little fluid can damage your
transaxle. Too much can mean that some of the
fluid could come out and fall on hot engine parts
or exhaust system parts, starting a fire. Too little
fluid could cause the transaxle to overheat. Be
sure to get an accurate reading if you check your
transaxle fluid.
Wait at least 30 minutes before checking the transaxle
fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.

In heavy traffic
-- especially in hot weather.

While pulling a trailer.
To get the right reading, the fluid should be at normal
operating temperature, which is 180F to 200F
(82C to 93C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50F
(10C). If it's colder than 50F (10C), you may
have to drive longer.

6-30 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 tighten wheel nuts in the
proper sequence to GM torque specifications.
Your rear drum brakes don't have wear indicators, but if
you ever hear a rear brake rubbing noise, have the rear
brake linings inspected immediately. Also, the rear
brake drums should be removed and inspected each
time the tires are removed for rotation or changing.
When you have the front brake pads replaced, have
the rear brakes inspected, too.
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.

6-34
6. Turn the bulb socket one-quarter turn and
remove it from the headlamp assembly.
7. Lift the plastic locking tab on the electrical
connector and pull the connector from the
headlamp bulb socket.
8. Connect the new headlamp bulb to the wiring
harness, making sure the connector tab snaps
into place.
9. Insert the bulb socket into the headlamp assembly.
10. Reverse all steps to reassemble the headlamp
assembly, then check the lamps.
11. Close the hood.Headlamp Aiming
Your vehicle has a headlamp system equipped with
horizontal and vertical aim indicators. The aim has been
pre
-set at the factory and should need no further
adjustment. This is true even though your vertical and
horizontal aim indicators may not fall exactly on the
ª0º (zero) marks on their scales.
If your vehicle is damaged in an accident, the headlamp
aim may be affected. Aim adjustment may be necessary
if it is difficult to see lane markers (for horizontal aim),
or if oncoming drivers flash their high beams at you
(for vertical aim). If you believe your headlamps need
to be re
-aimed, we recommend that you take it to
your dealer for service; however, it is possible for
you to re
-aim your headlamps as described in the
following procedure.
NOTICE:
To make sure your headlamps are aimed
properly, read all the instructions before
beginning. Failure to follow these instructions
could cause damage to headlamp parts.

6-41
Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service, see
your Buick Warranty booklet for details.
CAUTION:
Poorly maintained and improperly used tires
are dangerous.

Overloading your tires can cause
overheating as a result of too much friction.
You could have an air
-out and a serious
accident. See ªLoading Your Vehicleº in
the Index.
CAUTION: (Continued)
CAUTION: (Continued)

Underinflated tires pose the same danger
as overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.

Overinflated tires are more likely to be
cut, punctured or broken by a sudden
impact
-- such as when you hit a pothole.
Keep tires at the recommended pressure.

Worn, old tires can cause accidents.
If your tread is badly worn, or if your
tires have been damaged, replace them.

6-44
To reset (calibrate) the system:
1. Turn the ignition to RUN.
2. Locate the red RESET button inside of 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.
3. Press and hold the RESET button for about
five seconds.
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
two to eight 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 70 mph (110 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.
When rotating your tires, always use the correct rotation
pattern shown here.

6-46 Buying New Tires
To find out what kind and size of tires you need,
look at the Tire
-Loading Information label.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specification (TPC Spec)
number on each tire's sidewall. When you get new tires,
get ones with that same TPC Spec number. That way
your vehicle will continue to have tires that are designed
to give proper endurance, handling, speed rating,
traction, ride and other things during normal service
on your vehicle. If your tires have an all
-season
tread design, the TPC number will be followed by an
ªMSº (for mud and snow).
If you ever replace your tires with those not having
a TPC Spec number, make sure they are the same
size, load range, speed rating and construction type
(bias, bias
-belted or radial) as your original tires.
CAUTION:
Mixing tires could cause you to lose control while
driving. If you mix tires of different sizes or types
(radial and bias
-belted tires), the vehicle may not
handle properly, and you could have a crash.
Using tires of different sizes may also cause
damage to your vehicle. Be sure to use the
same size and type tires on all wheels.
It's all right to drive with your compact spare,
though. It was developed for use on your vehicle.
CAUTION:
If you use bias-ply tires on your vehicle, the
wheel rim flanges could develop cracks after
many miles of driving. A tire and/or wheel could
fail suddenly, causing a crash. Use only radial
-ply
tires with the wheels on your vehicle.

6-47 Uniform Tire Quality Grading
Quality grades can be found where applicable on the
tire sidewall between tread shoulder and maximum
section width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance.
(This applies only to vehicles sold in the United States.)
The grades are molded on the sidewalls of most
passenger car tires. The Uniform Tire Quality Grading
system does not apply to deep tread, winter
-type snow
tires, space
-saver or temporary use spare tires, tires with
nominal rim diameters of 10 to 12 inches (25 to 30 cm),
or to some limited
-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specified government test course.
For example, a tire graded 150 would wear one and a
half (1 1/2) times as well on the government course
as a tire graded 100. The relative performance of
tires depends upon the actual conditions of their use,
however, and may depart significantly from the norm
due to variations in driving habits, service practices and
differences in road characteristics and climate.
Traction
-- AA, A, B, C
The traction grades, from highest to lowest, are AA,
A, B, and C. Those grades represent the tire's ability to
stop on wet pavement as measured under controlled
conditions on specified government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight
-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.