2006 BUICK LACROSSE Owner's Manual

If you get the overheat warning 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. Set the climate controls to the highest heat setting
and fan speed and open the windows as necessary.
If you no longer have the overheat warning, you
can drive. Just to be safe, drive slower for about
10 minutes. If the warning does not come back on,
you can drive normally.
If the warning continues and you have not stopped,
pull over, stop, and park your vehicle right away.
If there is still no sign of steam, you can idle the
engine for three minutes while you are parked. If you
still have the warning, turn off the engine and get
everyone out of the vehicle until it cools down.
Also, see “Overheated Engine Protection Operating
Mode” later in this section.
You may decide not to lift the hood but to get service
help right away.Overheated Engine Protection
Operating Mode
This emergency operating mode allows your vehicle to
be driven to a safe place in an emergency situation.
If an overheated engine condition exists, an overheat
protection mode which alternates ring groups of
cylinders helps prevent engine damage. In this mode,
you will notice a signicant loss in power and engine
performance. The REDUCED POWER STOP WHEN
SAFE message will come on in the Driver Information
Center (DIC), along with the engine coolant temperature
warning light on the instrument panel, to indicate the
vehicle has entered overheated engine protection
operating mode. The temperature gage will also indicate
an overheat condition exists. Driving extended miles
(km) and/or towing a trailer in the overheat protection
mode should be avoided.
Notice:After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any
repair. The engine oil will be severely degraded.
Repair the cause of coolant loss, change the oil
and reset the oil life system. SeeEngine Oil
on page 5-15.
5-29

Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Coolant Recovery Tank
B. Radiator Pressure Cap
C. Electric Engine Cooling FansA. Coolant Recovery Tank
B. Pressure Cap
C. Electric Engine Cooling Fans
{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. 3.8L V6 Engine
3.6L V6 Engine
5-30

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.
When the engine is cold, the coolant level should be
at or above the cold ll line 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, the fans should be running.
If the fans are not running, 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 on
page 5-29for 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.
5-31

How to Add Coolant to the Coolant
Recovery Tank
{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.If you have not found a problem yet, but the coolant
level is not at the cold ll line, add a 50/50 mixture
of clean, drinkable water and DEX-COOL
®engine
coolant at the coolant recovery tank. SeeEngine
Coolant on page 5-24for more information.
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.
When the coolant level in the coolant recovery tank is at
the cold ll line, start the vehicle.
5-32

If the overheat warning continues, there is one more
thing you can try. You can add the proper coolant
mixture directly to the radiator, but be sure the system
is cool before you do it.
{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.
How to Add Coolant to the Radiator
(3.8L V6 Engine)
Notice:Your engine has a specic radiator ll
procedure. Failure to follow this procedure could
cause your engine to overheat and be severely
damaged.
1. You can remove the
radiator pressure cap
when the cooling
system, including the
radiator pressure cap
and upper radiator
hose, is no longer hot.
Turn the pressure cap
slowly counterclockwise
until it rst stops.
Do not press down while turning the pressure cap.
If you hear a hiss, wait for that to stop. A hiss
means there is still some pressure left.
2. Then keep turning the pressure cap, but now push
down as you turn it. Remove the pressure cap.
5-33

3. Open the coolant air
bleed valve located
on the thermostat
housing near the
heater hose. See
Engine Compartment
Overview on page 5-12
for more information
on location.
4. Fill the radiator with the proper DEX-COOL
®
coolant mixture, up to the base of the ller
neck. SeeEngine Coolant on page 5-24for more
information about the proper coolant mixture.
If you see a stream of coolant coming from the
air bleed valve, close the valve. Otherwise, close
the valve after the radiator is lled.
5. Rinse or wipe any spilled coolant from the engine
and the compartment.
5-34

6. Then ll the coolant recovery tank to the cold ll line.
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 you can feel the
upper radiator hose 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.
10. Then replace the radiator 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 pressure cap is hand-tight and fully seated.
11. Check the coolant in the recovery tank. The level in
the coolant recovery tank should be at the cold ll
line when the engine is cold.
5-35

How to Add Coolant to the Cooling
System (3.6L V6 Engine)
Notice:Your engine has a specic cooling system
drain and ll procedure. Failure to follow this
procedure could cause your engine to overheat
and be severely damaged. If your engine’s cooling
system needs to be drained and re-lled, please
see your dealer.
1. You can remove the
pressure cap when
the cooling system,
including the pressure
cap and upper radiator
hose is no longer hot.
Turn the pressure
cap slowly
counterclockwise.
If you hear a hiss, wait for that to stop. A hiss
means that there is still some pressure left.
2. Then keep turning the pressure cap and remove it.
{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.
3. Fill the cooling system with the proper DEX-COOL
®
coolant mixture, up to the base of the ller neck.
SeeEngine Coolant on page 5-24for more
information about the proper coolant mixture.
4. Rinse or wipe any spilled coolant from the engine
and the compartment.
5-36