BUICK CENTURY 2002 Owner's Manual

6-11
Engine Oil
If the LOW OIL light
appears on the instrument
cluster, 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.
Checking Engine Oil
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. See ªEngine Compartment
Overviewº in the Index for more information
on location.
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.
Pull out the dipstick and clean it with a paper towel or
cloth, then push it back in all the way. Remove it again,
keeping the tip down, and check the level.

6-12
When to Add Engine Oil
If the oil is at or below the ADD mark, then you'll need
to add at least one quart of oil. But you must use the
right kind. This part explains what kind of oil to use. For
engine oil crankcase capacity, see ªCapacities and
Specificationsº in the Index.
NOTICE:
Don't add too much oil. If your engine has
so much oil that the oil level gets above the
cross
-hatched area that shows the proper
operating range, your engine could be damaged.
The engine oil fill cap is located toward the front of the
engine near the engine oil dipstick handle. See ªEngine
Compartment Overviewº in the Index for more
information on location.

6-13
Be sure to fill it enough to put the level somewhere in
the proper operating range. Push the dipstick all the way
back in when you're through.
What Kind of Engine Oil to Use
Oils recommended for your vehicle can be identified by
looking for the starburst symbol.
This symbol indicates that the oil has been certified by
the American Petroleum Institute (API). Do not use any
oil which does not carry this starburst symbol.
If you change your own oil,
be sure you use oil that has
the starburst symbol on the
front of the oil container.
If you have your oil
changed for you, be sure
the oil put into your engine
is American Petroleum
Institute certified for
gasoline engines.
You should also use the proper viscosity oil for your
vehicle, as shown in the following chart:

6-14
As in the chart shown previously, SAE 5W-30 is best for
your vehicle. However, you can use SAE 10W
-30 if it's
going to be 0F (
-18C) or above. These numbers on
an oil container show its viscosity, or thickness. Do not
use other viscosity oils, such as SAE 20W
-50.
NOTICE:
Use only engine oil with the American
Petroleum Institute Certified For Gasoline
Engines starburst symbol. Failure to use the
recommended oil can result in engine damage
not covered by your warranty.
GM Goodwrench
oil meets all the requirements for
your vehicle.
If you are in an area where the temperature falls below
-20F (-29C), consider using either an SAE 5W-30
synthetic oil or an SAE 0W
-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Don't add anything to your oil. The recommended oils
with the starburst symbol are all you will need for good
performance and engine protection.
When to Change Engine Oil
(GM Oil Life System)
Your vehicle has a computer system that lets you know
when to change the engine oil and filter. This is based
on engine revolutions and engine temperature, and not
on mileage. Based on driving conditions, the mileage
at which an oil change will be indicated can vary
considerably. For the oil life system to work properly,
you must reset the system every time the oil is changed.
When the system has calculated that oil life has
been diminished, it will indicate that an oil change is
necessary. A CHANGE OIL SOON light will come on.
Change your oil as soon as possible within the next two
times you stop for fuel. It is possible that, if you are
driving under the best conditions, the oil life system
may not indicate that an oil change is necessary for over
a year. However, your engine oil and filter must be
changed at least once a year and at this time the system
must be reset. It is also important to check your oil
regularly and keep it at the proper level.
If the system is ever reset accidentally, you must change
your oil at 3,000 miles (5 000 km) since your last oil
change. Remember to reset the oil life system whenever
the oil is changed.

6-15
How to Reset the CHANGE OIL SOON Light
The GM Oil Life System
calculates when to change
your engine oil and filter based on vehicle use. Anytime
your oil is changed, reset the system so it can calculate
when the next oil change is required. If a situation
occurs where you change your oil prior to a CHANGE
OIL SOON light being turned on, reset the system.
After changing the engine oil, reset the system by
performing the following steps:
1. With the engine off, turn the ignition key to RUN.
2. Fully push and release the accelerator pedal slowly
three times within five seconds.
If the CHANGE OIL SOON light flashes, the
system is resetting.
3. Turn the key to OFF, then start the vehicle.
The oil life will change to 100 percent.
If the CHANGE OIL SOON light comes back on,
the system has not reset. Repeat the procedure.What to Do with Used Oil
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 threat to the environment. If you
change your own oil, be sure to drain all the oil from
the filter before disposal. Never 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.

6-16
Engine Air Cleaner/Filter
The engine air cleaner/filter is located underneath a
diagonal brace in the engine compartment on the driver's
side of the vehicle. See ªEngine Compartment Overviewº
in the Index for more information on location.
To check or replace the engine air cleaner/filter,
do the following:
1. Loosen the wing nut on the air duct.
2. Lift up on the two clips
located on the top of the
filter assembly.3. Then disconnect the duct and reposition it while
removing the side cover.
4. Pull out the filter.
5. Replace the filter if needed.
6. Be sure to reinstall the filter and install the cover
tightly when you are finished.
Refer to the Maintenance Schedule to determine when to
replace the air filter.
See ªScheduled Maintenance Servicesº in the Index.
CAUTION:
Operating the engine with the air cleaner/filter
off can cause you or others to be burned. The air
cleaner not only cleans the air, it stops flame if
the engine backfires. If it isn't there, and the
engine backfires, you could be burned. Don't
drive with it off, and be careful working on the
engine with the air cleaner/filter off.

6-17
NOTICE:
If the air cleaner/filter is off, a backfire can
cause a damaging engine fire. And, dirt can
easily get into your engine, which will damage it.
Always have the air cleaner/filter in place when
you're driving.
Passenger Compartment Air Filter
The passenger compartment
air filter is located
underneath your hood
below the windshield wiper
arm, on the passenger's side
(below the air inlet grille) of
the vehicle.The filter traps most of the pollen from the air entering
the air conditioning module. Like your engine's air
cleaner filter, it may need to be changed periodically.
For information on how often to change the passenger
compartment air filter, see ªMaintenance Scheduleº
in the Index.
To change the passenger compartment air filter, use the
following steps:
1. Turn off the ignition when the windshield wipers are
in the up position.
2. Raise the hood.
3. Disconnect the windshield washer pump hose from
the fender rail and air inlet grille.
4. Remove the hood weatherstrip from the passenger's
side of the vehicle (peel back halfway to center).
5. Remove the three air inlet grille retainers.
6. Remove the air inlet grille.

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.

6-20
Checking the Fluid Level
Prepare your vehicle as follows:

Park your vehicle on a level place. Keep the
engine running.

With the parking brake applied, place the shift
lever in PARK (P).

With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the shift
lever in PARK (P).

Let the engine run at idle for three to five minutes.Then, without shutting off the engine, follow these steps:
The automatic transaxle fluid dipstick handle is the red
loop located toward the rear of the engine. See ªEngine
Compartment Overviewº in the Index for more
information on location.
1. Pull out the dipstick and wipe it with a clean rag or
paper towel.
2. Push it back in all the way, wait three seconds and
then pull it back out again.