2009 CHEVROLET TAHOE engine overheat

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 FULL COLD mark.
5. Replace the pressure cap. Be sure the pressure
cap is hand-tight and fully seated.
6. Verify coolant level after engine is shut off and the
coolant is cold. If necessary, repeat coolant ll
procedure Steps 1 through 6.Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
Coolant Surge Tank Pressure Cap
If your vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 5-14for more
information on location.
Engine Overheating
The vehicle has several indicators to warn of engine
overheating.
There is a coolant temperature gage on your vehicle’s
instrument panel. SeeEngine Coolant Temperature
Gage on page 3-42.
5-34

In addition, ENGINE OVERHEATED STOP ENGINE,
ENGINE OVERHEATED IDLE ENGINE, and a ENGINE
POWER IS REDUCED message comes on in the
Driver Information Center (DIC) on the instrument panel.
SeeDIC Warnings and Messages on page 3-64.
You may decide not to lift the hood when this warning
appears, but instead get service help right away.
SeeRoadside Assistance Program on page 7-7.
If you do decide 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, both fans should
be running. If they are not, do not continue to run
the engine and have the vehicle serviced.
Notice:Engine damage from running your engine
without coolant is not covered by your warranty. See
Overheated Engine Protection Operating Mode on
page 5-36for information on driving to a safe place
in an emergency.
Notice:If the engine catches re while driving
with no coolant, the vehicle can be badly damaged.
The costly repairs would not be covered by the
vehicle warranty. SeeOverheated Engine Protection
Operating Mode on page 5-36for information on
driving to a safe place in an emergency.If Steam Is Coming From The Engine
Compartment
{CAUTION:
Steam from an overheated engine can burn you
badly, even if you just open the hood. Stay away
from the engine if you see or hear steam coming
from it. Turn it off and get everyone away from
the vehicle until it cools down. Wait until there
is no sign of steam or coolant before you open
the hood.
If you keep driving when the vehicles engine is
overheated, the liquids in it can catch re. You or
others could be badly burned. Stop the engine if it
overheats, and get out of the vehicle until the
engine is cool.
SeeOverheated Engine Protection Operating
Mode on page 5-36for information on driving to a
safe place in an emergency.
5-35

If No Steam Is Coming From The
Engine Compartment
The ENGINE OVERHEATED STOP ENGINE or the
ENGINE OVERHEATED IDLE ENGINE message, along
with a low coolant condition, can indicate a serious
problem.
If you get an engine overheat warning, but see or
hear no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. SeeTowing a Trailer on page 4-50.
If you get the ENGINE OVERHEATED STOP ENGINE or
the ENGINE OVERHEATED IDLE ENGINE message
with no sign of steam, try this for a minute or so:
If the overheat warning is displayed with no sign of
steam:
1. Turn the air off.
2. Turn the heater on to the highest temperature and
to the highest fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle in N (Neutral)
while stopped. If it is safe to do so, pull off the
road, shift to P (Park) or N (Neutral) and let
the engine idle.If the temperature overheat gage is no longer in the
overheat zone or an overheat warning no longer displays,
the vehicle can be driven. Continue to drive the vehicle
slow for about 10 minutes. Keep a safe vehicle distance
from the car in front of you. If the warning does not come
back on, continue to drive normally.
If the warning continues, pull over, stop, and park the
vehicle right away.
If there is no sign of steam, idle the engine for
three minutes while parked. If the warning is still
displayed, turn off the engine until it cools down.
Also, see “Overheated Engine Protection Operating
Mode” later in this section.Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
ENGINE POWER IS REDUCED message 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 the 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.
5-36

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.
Engine Fan Noise
If the vehicle has a clutched engine cooling fan, when the
clutch is engaged, the fan spins faster to provide more air
to cool the engine. In most everyday driving conditions,
the fan is spinning slower and the clutch is not fully
engaged. This improves fuel economy and reduces fan
noise. Under heavy vehicle loading, trailer towing, and/or
high outside temperatures, the fan speed increases as
the clutch more fully engages, so you may hear an
increase in fan noise. This is normal and should not be
mistaken as the transmission slipping or making extra
shifts. It is merely the cooling system functioning properly.
The fan will slow down when additional cooling is not
required and the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.If the vehicle has electric cooling fans, you may hear
the fans spinning at low speed during most everyday
driving. The fans may turn off if no cooling is required.
Under heavy vehicle loading, trailer towing, and/or
high outside temperatures, or if you are operating the
air conditioning system, the fans may change to
high speed and you may hear an increase in fan noise.
This is normal and indicates that the cooling system
is functioning properly. The fans will change to low
speed when additional cooling is no longer required.
Power Steering Fluid
If the vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
SeeEngine Compartment
Overview on page 5-14for
reservoir location.
5-37

Electrical System (cont.)
Power Windows and Other Power Options....5-114
Underhood Fuse Block...............................5-118
Windshield Wiper Fuses.............................5-114
Electronic Immobilizer
PASS-Key
®III+...........................................2-24
Electronic Immobilizer Operation
PASS-Key
®III+...........................................2-24
Engine
Air Cleaner/Filter.........................................5-20
Check and Service Engine Soon Lamp...........3-43
Coolant......................................................5-29
Coolant Heater............................................2-30
Coolant Temperature Gage...........................3-42
Drive Belt Routing.......................................6-16
Engine Compartment Overview......................5-14
Exhaust.....................................................2-50
Fan Noise..................................................5-37
Oil .............................................................5-15
Oil Life System...........................................5-18
Overheated Protection Operating Mode...........5-36
Overheating................................................5-34
Starting......................................................2-28
Entry Lighting.................................................3-19
Event Data Recorders.....................................7-17
Exit Lighting...................................................3-19
Extender, Safety Belt.......................................1-54
Exterior Lamps...............................................3-14
F
Filter
Engine Air Cleaner......................................5-20
Finish Damage.............................................5-112
Flashers, Hazard Warning.................................. 3-6
Flash-to-Pass................................................... 3-8
Flat Tire........................................................5-85
Flat Tire, Changing.........................................5-86
Flat Tire, Storing...........................................5-101
Fluid
Automatic Transmission........................5-22, 5-25
Power Steering...........................................5-37
Windshield Washer......................................5-39
Fog Lamp
Fog ...........................................................3-17
Fog Lamp Light..............................................3-49
Four-Wheel Drive....................................2-40, 5-52
Front Axle......................................................5-53
Fuel............................................................... 5-5
Additives...................................................... 5-6
California Fuel.............................................. 5-6
Driving for Better Economy............................. 4-2
E85 (85% Ethanol)........................................ 5-7
Filling a Portable Fuel Container....................5-12
Filling the Tank............................................. 5-9
Fuels in Foreign Countries.............................. 5-8
Gage .........................................................3-50
5

N
Navigation System, Privacy..............................7-18
Navigation/Radio System, see Navigation
Manual.....................................................3-114
New Vehicle Break-In......................................2-26
O
Odometer......................................................3-36
Odometer, Trip...............................................3-36
Off-Road Driving.............................................4-13
Off-Road Recovery..........................................4-11
Oil
Engine.......................................................5-15
Pressure Gage............................................3-46
Pressure Light.............................................3-48
Oil, Engine Oil Life System..............................5-18
Older Children, Restraints................................1-55
Online Owner Center........................................ 7-5
OnStar, Privacy..............................................7-18
OnStar
®System, see OnStar®Manual...............2-68
Operation, Universal Home Remote System........2-72
Outlet Adjustment............................................3-30
Outlets
Accessory Power.........................................3-20
Outside
Automatic Dimming Mirror.............................2-55
Convex Mirror.............................................2-55
Heated Mirrors............................................2-55Outside (cont.)
Manual Mirrors............................................2-52
Power Foldaway Mirrors...............................2-54
Power Mirrors.............................................2-53
Towing Mirrors............................................2-53
Overheated Engine Protection Operating Mode . . . 5-36
Owner Checks and Services.............................6-10
Owners, Canadian.............................................. iii
P
Paint, Damage..............................................5-112
Park
Shifting Into................................................2-47
Shifting Out of............................................2-49
Park Aid................................................2-56, 2-62
Park Brake....................................................2-45
Park Tilt Mirrors..............................................2-55
Parking
Assist........................................................2-56
Over Things That Burn.................................2-49
Passenger Airbag Status Indicator.....................3-38
Passenger Sensing System..............................1-90
Passing.........................................................4-11
PASS-Key
®III+ Electronic Immobilizer...............2-24
PASS-Key®III+ Electronic Immobilizer Operation . . . 2-24
Perchlorate Materials Requirements, California...... 5-4
Phone
Bluetooth
®................................................3-115
9