2004 BUICK CENTURY engine

If No Steam Is Coming From Your
Engine
An overheated engine warning can indicate a serious
problem.
If there is an overheated engine warning and you do not
see or hear any steam, the problem may not be too
serious. Sometimes the engine can get a little too hot
when the vehicle:
Climbs a long hill on a hot day.
Stops after high-speed driving.
Idles for long periods in traffic.
Tows a trailer.
If an overheated engine warning appears with no sign of
steam, try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL (N)
while stopped. If it is safe to do so, pull off the road,
shift to PARK (P) or NEUTRAL (N) and let the
engine idle.2. Adjust the heater to the highest temperature and
fan speed settings and open the window as
necessary.
If the overheated engine warnings no longer exist, you
can drive. Just to be safe, drive slower for about
10 minutes. If the warnings do not come back on, you
can drive normally.
If the warning continues, and you have not stopped, pull
over, stop, and park the vehicle right away.
If there is still no sign of steam, idle the engine for three
minutes while you are parked. If the warning still
exists,turn off the engine and get everyone out of the
vehicleuntil it cools down. Also, see “Overheated
Engine Protection Operating Mode” listed previously in
this section.
You may decide not to lift the hood but to get service
help right away.
5-27

Cooling System
When it is safe to lift the hood, this is what will be seen:
A. Coolant Recovery Tank
B. Electric Engine Cooling Fan
C. Radiator Pressure Cap{CAUTION:
An electric engine cooling fan under the hood
can start up even when the engine is not
running and can injure you. Keep hands,
clothing and tools away from any underhood
electric fan.
If the coolant inside the coolant recovery tank is boiling,
do not do anything else until it cools down. The
vehicle should be parked on a level surface.
5-28

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.
5-29

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