2004 BUICK CENTURY Owner's Manual

When the engine is cold,
the coolant level should be
at or above the COLD
mark on the coolant
recovery tank. If it is not,
there may be a leak
at the pressure cap or in
the radiator hoses,
heater hoses, radiator,
water pump, or somewhere
else in the cooling
system.
{CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Do not touch them. If
you do, you can be burned.
Do not run the engine if there is a leak. If you
run the engine, it could lose all coolant. That
could cause an engine re, and you could be
burned. Get any leak xed before you drive the
vehicle.If there seems to be no leak, with the engine on, check
to see if the electric engine cooling fans are running.
If the engine is overheating, both fans should be
running. If they are not the vehicle needs service.
Notice:Engine damage from running your engine
without coolant is not covered by your warranty. See
“Overheated Engine Protection Operating Mode”
in the Index for information on driving to a safe
place in an emergency.
Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by your warranty. Always use
DEX-COOL
®(silicate-free) coolant in your vehicle.
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How to Add Coolant to the Coolant
Recovery Tank
If a problem has not been found yet, but the coolant
level is not at the COLD mark, add a 50/50 mixture of
clean, drinkable water and DEX-COOL
®engine
coolant at the coolant recovery tank. SeeEngine
Coolant on page 5-22for more information.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as 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 would not get the overheat warning.
Your engine could catch re and you or others
could be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.Notice:In cold weather, water can freeze and crack
the engine, radiator, heater core and other parts.
Use the recommended coolant and the proper
coolant mixture.
{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. Do not spill coolant on a hot engine.
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When the coolant in the coolant recovery tank is at the
COLD mark, start the vehicle.
If the overheated engine warnings continue, there is
one more thing that can be done. Add the proper coolant
mixture directly to the radiator, but be sure the cooling
system is cool before this is done.
{CAUTION:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They
are under pressure, and if you turn the radiator
pressure cap — even a little — they can come
out at high speed. Never turn the cap when the
cooling system, including the radiator pressure
cap, is hot. Wait for the cooling system and
radiator pressure cap to cool if you ever have
to turn the pressure cap.
5-31

How to Add Coolant to the Radiator
Notice:Your engine has a specic radiator
ll procedure. Failure to follow this procedure could
cause your engine to overheat and be severely
damaged.
Remove the radiator pressure cap when the cooling
system, including the radiator pressure cap and upper
radiator hose, is no longer hot.
1. Turn the pressure cap slowly counterclockwise at
its rst stop. Do not press down while turning the
pressure cap.If a hiss is heard, wait for it to stop. A hiss means
there is still some pressure left.
2. Keep turning the pressure cap, but now push down
as you turn it. Remove the pressure cap.
{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. Do not spill coolant on a hot engine.
5-32

3. After the engine cools, open the coolant air bleed
valves. There are two bleed valves.
One is located on the
thermostat housing.
The other is located on the
thermostat bypass tube.4. Fill the radiator with the
proper DEX-COOL®
coolant mixture,
up to the base of the
ller neck. See
Engine Coolant on
page 5-22for more
information about the
proper coolant mixture.
If a stream of coolant is coming from an air bleed
valve, close the valve. Otherwise, close the
valves after the radiator is lled.
5. Rinse or wipe any spilled coolant from the engine
and the compartment.
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6. Then ll the coolant recovery tank to the COLD
mark on the coolant recovery tank.
7. Put the cap back on the coolant recovery tank, but
leave the radiator pressure cap off.8. Start the engine and let it run until the upper
radiator hose feels it is getting hot. Watch out for the
engine cooling fans.
9. By this time, the coolant level inside the radiator
ller neck may be lower. If the level is lower, add
more of the proper DEX-COOL
®coolant mixture
through the ller neck until the level reaches
the base of the ller neck.
5-34

10. Then replace the pressure cap. At any time during
this procedure if coolant begins to ow out of the
ller neck, reinstall the pressure cap. Be sure
the arrow on the pressure cap lines up like this.
11. Check the coolant in the recovery tank. The level in
the coolant recovery tank should be at the HOT
mark when the engine is hot or at the COLD mark
when the engine is cold.
Power Steering Fluid
The power steering uid reservoir is located at the back
of the engine compartment, on the passenger’s side
of the vehicle.
SeeEngine Compartment Overview on page 5-12for
reservoir location.
5-35

When to Check Power Steering Fluid
It is not necessary to regularly check power steering uid
unless there appears to be a leak in the system or an
unusual noise is heard. A uid loss in this system could
indicate a problem. Have the system inspected and
repaired.
How to Check Power Steering Fluid
Turn the key off, let the engine compartment cool down,
wipe the cap and the top of the reservoir clean, then
unscrew the cap and wipe the dipstick with a clean rag.
Replace the cap and completely tighten it. Then
remove the cap again and look at the uid level on the
dipstick.
When the engine
compartment is hot, the
level should be at the
H (hot) mark. When it is
cold, the level should be at
the C (cold) mark. If the
uid is at the ADD
mark, uid should be
added.
What to Use
To determine what kind of uid to use, see
Recommended Fluids and Lubricants on page 6-12.
Always use the proper uid. Failure to
use the proper uid can cause leaks and damage
hoses and seals.
Windshield Washer Fluid
What to Use
When the vehicle needs windshield washer uid, be
sure to read the manufacturer’s instructions before use.
If the vehicle will be operating in an area where the
temperature may fall below freezing, use a uid that has
sufficient protection against freezing.
5-36