Page 241 of 362

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-10999169) -
2018 - crc - 3/28/17
240 Vehicle Care
3.6L V6 Engine
1. Engine Cooling Fans (Outof View)
2. Coolant Surge Tank and Pressure Cap
{Warning
An underhood electric fan can
start up even when the engine is
not running and can cause injury.
Keep hands, clothing, and tools
away from any underhood
electric fan.
{Warning
Do not touch heater or radiator
hoses, or other engine parts.
They can be very hot and can
burn you. Do not run the engine if
there is a leak; all coolant could
leak out. That could cause an
engine fire and can burn you. Fix
any leak before driving the
vehicle.
Engine Coolant
The cooling system in the vehicle is
filled with DEX-COOL engine
coolant. This coolant needs to be
checked and replaced at
appropriate intervals. See
Maintenance Schedule 0311.
The following explains the cooling
system and how to check and add
coolant when it is low. If there is a
problem with engine overheating,
see Engine Overheating 0243.
What to Use
{Warning
Plain water, or other liquids such
as alcohol, can boil before the
proper coolant mixture will. With
plain water or the wrong mixture,
the engine could get too hot but
there would not be an overheat
warning. The engine could catch
fire and you or others could be
burned.
Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
coolant. If using this mixture,
nothing else needs to be added.
This mixture:
. Gives freezing protection down
to−37 °C (−34 °F), outside
temperature
. Gives boiling protection up to
129 °C (265 °F), engine
temperature
. Protects against rust and
corrosion
. Will not damage aluminum parts
Page 243 of 362

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-10999169) -
2018 - crc - 3/28/17
242 Vehicle Care
The coolant surge tank is in the
engine compartment on the driver
side of the vehicle. SeeEngine
Compartment Overview 0231.
How to Add Coolant to the
Coolant Surge Tank
If no problem is found, check to see
if coolant is visible in the coolant
surge tank. If coolant is visible but
the coolant level is not at the
indicated level mark, add a 50/
50 mixture of clean, drinkable water
and DEX-COOL coolant at the
coolant surge tank, but be sure the
cooling system, including the
coolant surge tank pressure cap, is
cool before you do it.
{Warning
Steam and scalding liquids from a
hot cooling system are under
pressure. Turning the pressure
cap, even a little, can cause them
to come out at high speed and
you could be burned. Never turn
the cap when the cooling system,
(Continued)
Warning (Continued)
including the pressure cap, is hot.
Wait for the cooling system and
pressure cap to cool.
{Warning
Plain water, or other liquids such
as alcohol, can boil before the
proper coolant mixture will. With
plain water or the wrong mixture,
the engine could get too hot but
there would not be an overheat
warning. The engine could catch
fire and you or others could be
burned.
{Warning
Spilling coolant on hot engine
parts can burn you. Coolant
contains ethylene glycol and it will
burn if the engine parts are hot
enough.
Caution
Failure to follow the specific
coolant fill procedure could cause
the engine to overheat and could
cause system damage. If coolant
is not visible in the surge tank,
contact your dealer.
1. Remove the coolant surge tankpressure cap when the cooling
system, including the coolant
surge tank pressure cap and
upper radiator hose, is no
longer hot.
Turn the pressure cap slowly
counterclockwise about
one-quarter of a turn. If you
hear a hiss, wait for that to
stop. This will allow any
pressure still left to be vented
out the discharge hose.
Page 244 of 362

Buick LaCrosse Owner Manual (GMNA-Localizing-U.S./Canada-10999169) -
2018 - crc - 3/28/17
Vehicle Care 243
2. Keep turning the pressure capslowly and remove it.
3. Fill the coolant surge tank with the proper mixture to the
indicated level mark.
4. With the coolant surge tank pressure cap off, start the
engine and let it run until you
can feel the upper radiator
hose getting hot. Watch out for
the engine cooling fan.
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper
mixture to the coolant surge
tank until the level reaches the
indicated level mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1–6. If the coolant still is not at the
proper level when the system
cools down again, see your
dealer.
Caution
If the pressure cap is not tightly
installed, coolant loss and engine
damage may occur. Be sure the
cap is properly and tightly
secured.
Engine Overheating
The vehicle has several indicators
to warn of the engine overheating.
The instrument cluster has an
engine coolant temperature gauge
and an engine coolant temperature
warning light.
See
Engine Coolant Temperature
Gauge 0114 and Engine Coolant
Temperature Warning Light 0122.
The vehicle may also display a
message on the Driver Information
Center (DIC). If the decision is made not to lift the
hood when this warning appears,
get service help right away. See
Roadside Assistance Program
0
329.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface. Then
check to see if the engine cooling
fans are running. If the engine is
overheating, the fans should be
running. If they are not, do not
continue to run the engine. Have the
vehicle serviced.Caution
Do not run the engine if there is a
leak in the engine cooling system.
This can cause a loss of all
coolant and can damage the
system and vehicle. Have any
leaks fixed right away.