2008 BUICK LUCERNE engine overheat

Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
message ENGINE OVERHEATED STOP ENGINE is
displayed, an overheat protection mode which alternates
ring groups of cylinders helps prevent engine damage.
In this mode, you will notice a loss in power and
engine performance. This operating mode allows your
vehicle to be driven to a safe place in an emergency.
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.
Cooling System (3.8L V6 Engine)
When you decide it is safe to lift the hood, here is what
you will see:
A. Radiator Pressure Cap
B. Coolant Recovery Tank
C. Electric Engine Cooling Fans
5-30

{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.
The coolant level should be at or above the FULL
COLD mark when the engine is cold. The coolant level
should be above the FULL COLD mark under normal
operating conditions. If it is not, you may have 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, your vehicle needs service.
Notice:Engine damage from running the engine
without coolant is not covered by the warranty.
Notice:Using coolant other than DEX-COOL
®may
cause premature engine, heater core, or radiator
corrosion. In addition, the engine coolant could
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by the warranty. Always
use DEX-COOL
®(silicate-free) coolant in the vehicle.
5-31

How to Add Coolant to the Coolant
Recovery Tank
{CAUTION:
Adding only plain water to the cooling system
can be dangerous. Plain water, or some other
liquid such as alcohol, can boil before the
proper coolant mixture will. The vehicle’s
coolant warning system is set for the proper
coolant mixture. With plain water or the wrong
mixture, the engine could get too hot but you
would not get the overheat warning. The
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.If you have not found a problem yet, but the coolant
level is not at the FULL COLD mark, add a
50/50 mixture ofclean, drinkable waterand
DEX-COOL
®engine coolant at the coolant recovery
tank. SeeEngine Coolant on page 5-24for more
information.
{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 in the coolant recovery tank is at the
FULL COLD mark, start your vehicle.
5-32

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, your 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 5-30for 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 could
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by the warranty. Always
use DEX-COOL
®(silicate-free) coolant in the vehicle.
How to Add Coolant to the Coolant
Surge Tank
If you have not found a problem yet, check to see if
coolant is visible in the surge tank. If coolant is visible
but the level is not at the FULL COLD mark located
on the side of the surge tank, add enough of a 50/50
mixture of clean, drinkable water and DEX-COOL
®
coolant at the coolant surge tank to bring the level to
the FULL COLD mark, but be sure the cooling system,
including the coolant surge tank pressure cap (if
equipped), is cool before you do it. SeeEngine Coolant
on page 5-24for more information.
5-37

If no coolant is visible in the surge tank, add coolant as
follows:
{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 coolant
surge tank pressure cap — even a little — they
can come out at high speed. Never turn the
cap when the cooling system, including the
coolant surge tank pressure cap, is hot. Wait
for the cooling system and coolant surge tank
pressure cap to cool if you ever have to turn
the pressure cap.
{CAUTION:
Adding only plain water to the cooling system
can be dangerous. Plain water, or some other
liquid such as alcohol, can boil before the
proper coolant mixture will. The vehicle’s
coolant warning system is set for the proper
coolant mixture. With plain water or the wrong
mixture, the engine could get too hot but you
would not get the overheat warning. The
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.
5-38

DDaytime Running Lamps..................................3-16
Defensive Driving............................................. 4-2
Delayed Entry Lighting.....................................3-18
Delayed Exit Lighting.......................................3-18
Delayed Locking.............................................2-11
DIC Compass.................................................3-54
Disc, MP3......................................................3-89
Doing Your Own Service Work........................... 5-4
Door
Delayed Locking..........................................2-11
Locks........................................................2-10
Power Door Locks.......................................2-10
Programmable Automatic Door Locks.............2-11
Rear Door Security Locks.............................2-12
Driver Information Center (DIC).........................3-48
DIC Operation and Displays..........................3-49
DIC Vehicle Customization............................3-66
DIC Warnings and Messages........................3-56
Driving
At Night.....................................................4-11
Before a Long Trip......................................4-13
Defensive..................................................... 4-2
Drunken....................................................... 4-2
Highway Hypnosis.......................................4-13
Hill and Mountain Roads..............................4-14
In Rain and on Wet Roads...........................4-12
Rocking Your Vehicle to Get it Out.................4-19
Winter........................................................4-15
Dual Automatic Climate Control System.............3-24E
EDR .............................................................7-17
Electrical System
Add-On Equipment.....................................5-105
Fuses and Circuit Breakers.........................5-105
Power Windows and Other Power Options....5-105
Rear Underseat Fuse Block.........................5-108
Underhood Fuse Block...............................5-106
Engine
Air Cleaner/Filter.........................................5-20
Check and Service Engine Soon Light............3-44
Coolant......................................................5-24
Coolant Heater............................................2-24
Coolant Temperature Gage...........................3-43
Coolant Temperature Warning Light................3-42
Drive Belt Routing.......................................6-14
Engine Compartment Overview......................5-12
Exhaust.....................................................2-32
Oil .............................................................5-15
Oil Life System...........................................5-18
Overheated Protection Operating Mode...........5-30
Overheating................................................5-28
Running While Parked..................................2-33
Starting......................................................2-22
Entry Lighting.................................................3-18
Event Data Recorders.....................................7-18
Extender, Safety Belt.......................................1-32
Exterior Lamps...............................................3-14
Exterior Lighting Battery Saver..........................3-17
4

O
Odometer......................................................3-34
Odometer, Trip...............................................3-34
Off-Road Recovery........................................... 4-9
Oil
Engine.......................................................5-15
Pressure Light.............................................3-46
Oil, Engine Oil Life System..............................5-18
Older Children, Restraints................................1-33
Online Owner Center........................................ 7-5
OnStar, Privacy..............................................7-19
OnStar
®System, see OnStar®Manual...............2-46
Operation, Universal Home Remote System........2-50
Other Warning Devices...................................... 3-6
Outlet Adjustment............................................3-30
Outlets
Accessory Power.........................................3-20
Outside
Automatic Dimming Heated Mirror..................2-38
Convex Mirror.............................................2-38
Power Mirrors.............................................2-37
Overheated Engine Protection Operating Mode . . . 5-30
Owner Checks and Services.............................. 6-8
Owners, Canadian............................................... ii
P
Paint, Damage..............................................5-102
Panic Brake Assist............................................ 4-7
Park Aid........................................................2-39
Park Brake....................................................2-27
Park (P)
Shifting Into................................................2-28
Shifting Out of............................................2-31
Park Tilt Mirrors..............................................2-38
Parking
Assist........................................................2-39
Over Things That Burn.................................2-32
Passenger Airbag Status Indicator.....................3-36
Passenger Compartment Air Filter.....................3-30
Passenger Sensing System..............................1-67
Passing........................................................... 4-9
PASS-Key
®III+..............................................2-18
PASS-Key®III+ Operation................................2-19
Perchlorate Materials Requirements, California...... 5-4
Perimeter Lighting...........................................3-18
Power
Door Locks.................................................2-10
Electrical System.......................................5-105
Inadvertent Battery Saver.............................3-19
Lumbar Controls........................................... 1-3
Retained Accessory (RAP)............................2-22
9