engine BUICK CENTURY 1998 Manual PDF

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6-13 What Kind of Engine Oil to Use
Oils recommended for your vehicle can be identified by
looking for the ªStarburstº 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:

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6-14
As shown in the chart, SAE 10W-30 is best for your
vehicle. However, you can use SAE 5W
-30 if it's going
to be colder than 60F (16C) before your next oil
change. When it's very cold, you should use SAE
5W
-30. 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
ªStarburstº 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. Your dealer is ready to
advise if you think something should be added.
When to Change Engine Oil
If any one of these is true for you, use the short trip/city
maintenance schedule:

Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures are below freezing.

Most trips include extensive idling (such as frequent
driving in stop
-and-go traffic).

Most trips are through dusty areas.

You frequently tow a trailer or use a carrier on top of
your vehicle.

The vehicle is used for delivery service, police, taxi
or other commercial application.
Driving under these conditions causes engine oil to
break down sooner. If any one of these is true for your
vehicle, then you need to change your oil and filter
every 3,000 miles (5 000 km) or 3 months
-- whichever
occurs first.

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6-15
If none of them is true, use the long trip/highway
maintenance schedule. Change the oil and filter every
7,500 miles (12 500 km) or 12 months
-- whichever
occurs first. Driving a vehicle with a fully warmed
engine under highway conditions causes engine oil to
break down slower.
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.
Engine Air Cleaner/Filter
As you face the front of the vehicle, the engine air
cleaner is in the front right section of the engine
compartment. There is a filter inside the air cleaner.

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6-16
Remove the air cleaner assembly as follows:
1. Remove the air duct clamp and separate the hose
from the air cleaner cover. Rotate the hose on the
throttle body upward so it is out of the way.
2. Detach the electrical connector and remove the air
cleaner cover by flipping the two latches on the
bottom inboard side of the cover.
3. Tilt and pull the cover toward the engine to
disengage it from the assembly.
4. Remove the old filter and install the new one.
5. Reinstall the air cleaner cover by sliding the tabs into
the base of the air cleaner and locking the two
latches. Reinstall the electrical connector.
6. Rotate the inlet duct into position and slide it onto
the air cleaner outlet, then tighten the clamp.
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.
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.

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6-17
Supercharger Oil
Unless you are technically
qualified and have the
proper tools, you should let
your dealer or a qualified
service center perform this
maintenance.
When to Check
Check oil level every 30,000 miles (50 000 km) or every
36 months, whichever occurs first.
What Kind of Oil to Use
See ªRecommended Fluids and Lubricantsº in the Index
and use only the recommended oil.
How to Check and Add Oil
Check oil only when the engine is cold. Allow the
engine to cool two to three hours after running.
CAUTION:
If you remove the supercharger oil fill plug while
the engine is hot, pressure may cause hot oil to
blow out of the oil fill hole. You may be burned.
Do not remove the plug until the engine cools.
1. Clean the area around the oil fill plug before
removing it.
2. Remove the oil fill plug using a 3/16 inch
Allen wrench.
3. The oil level is correct when it just reaches the
bottom of the threads of the inspection hole.
4. Replace the oil plug with the O
-ring in place. Torque
to 88 lb
-in (10 N´m).

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6-18
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.
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. 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).

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6-19
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.
Checking the Fluid Level

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:
1. The transaxle fluid
dipstick is a round, red
loop located next to the
brake master cylinder.
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.
3. Check both sides of the dipstick, and read the
lower level. The fluid level must be in the
cross
-hatched area.
4. If the fluid level is in the acceptable range, push the
dipstick back in all the way.

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6-20 How to Add Fluid
Refer to the Maintenance Schedule to determine what
kind of transaxle fluid to use. See ªRecommended
Fluids and Lubricantsº in the Index.
If the fluid level is low, add only enough of the proper
fluid to bring the level into the cross
-hatched area on
the dipstick.
1. Pull out the dipstick.
2. Using a long
-neck funnel, add enough fluid at the
dipstick hole to bring it to the proper level.
It doesn't take much fluid, generally less than one
pint (0.5 L). Don't overfill.
NOTICE:
We recommend you use only fluid labeled
DEXRON
-III, because fluid with that label is
made especially for your automatic transaxle.
Damage caused by fluid other than
DEXRON

-III is not covered by your new
vehicle warranty.
3. After adding fluid, recheck the fluid level as
described under ªHow to Check.º
4. When the correct fluid level is obtained, push the
dipstick back in all the way.
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, a GM cap
is recommended.

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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.