2008 Lexus GS450h coolant temperature

148
GS_HV_U
December 12, 2007 3:50 pm
2-2. Instrument cluster
Gauges and meters
The units used on the speedometer may differ depending on the target
region.

The following gauges, meters and display illuminate when the
“POWER” switch is in ON mode.
Power meter
Displays the instantaneous output from the hybrid system is approximate
kilowatts.
Speedometer
Displays the vehicle speed.
Fuel gauge
Displays the quantity of fuel remaining in the tank.
Engine coolant temperature gauge
Displays the engine coolant temperature.
Multi-information display
 P. 1 5 5

151
2-2. Instrument cluster
2
When driving
GS_HV_U
December 12, 2007 3:50 pm
NOTICE
■To prevent damage to the engine and its components
The engine may be overheating if the engine coolant temperature gauge is in the
red zone (“H”). In this case, immediately stop the vehicle in a safe place. Check the
engine after it has cooled completely. ( P. 5 3 8 )
■To activate the light sensitivity function properly
Do not affix a sticker or window tint to the rear window glass, or put an object
behind the rear seat.

416
4-3. Do-it-yourself maintenance
GS_HV_U
December 27, 2007 1:38 pm
CAUTION
The engine compartment contains many mechanisms and fluids that may move sud-
denly, become hot, or become electrically energized. To avoid death or serious injury,
observe the following precautions.
■When working on the engine compartment
●Keep hands, clothing, and tools away from the moving fan and engine drive belt.
●Be careful not to touch the engine, power control unit, radiator, exhaust manifold,
etc. right after driving as they may be hot. Oil and other fluids may also be hot.
●Do not leave anything that may burn easily , such as paper or rags, in the engine
compartment.
●Do not smoke, cause sparks or expose an open flame to fuel. Fuel fumes are flam-
mable.
■When working near the electric cooling fan or radiator grille
Be sure the “POWER” switch is OFF. 
With the “POWER” switch in ON mode, the electric cooling fan may automatically
start to run if the air conditioning is on and/or the coolant temperature is high. 
(  P. 4 2 8 )
■Safety glasses
Wear safety glasses to prevent flying or fall ing material, fluid spray, etc. from getting
in the eyes.
NOTICE
■If you remove the air cleaner filter
Driving with the air cleaner filter removed may cause excessive engine wear due to
dirt in the air. Also a backfire could cause a fire in the engine compartment.

538
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
If your vehicle overheats
If your hybrid system overheats:
Stop the vehicle in a safe place and turn off the air conditioning
system.
Check to see if steam is coming out from under the hood.
If you see steam: 
Stop the hybrid system and carefully lift the hood.
If you do not see steam: Leave the hybrid system running and carefully lift the hood.
Remove the engine compartment cover. ( P. 421)
Check to see if the cooling fan is operating.
If the fan is operating: 
Wait until the engine coolant temperature gauge begins to
fall and then stop the hybrid system.
If the fan is not operating: 
Stop the hybrid system immed iately and call your local
Lexus dealer.
After the hybrid system has
cooled down sufficiently, check
the coolant level and inspect the
radiator core (radiator) for any
leaks.STEP1
STEP2
STEP3
STEP4
STEP5

5
When trouble arises
539
5-2. Steps to take in an emergency
GS_HV_U
December 12, 2007 3:50 pm
■Overheating
In the following situations, your vehicle may be overheating.
●The engine coolant temperature gauge enters the red zone or a loss of power is
experienced.
●Steam is coming from under the hood.
●The message “HYBRID SYSTEM OVERHEAT” is displayed on the multi-infor-
mation display.
CAUTION
■To prevent an accident or injury when in specting under the hood of your vehicle
●Keep hands and clothing away from the fan and engine drive belt while the hybrid
system is running.
●Do not loosen the radiator cap while the hybrid system and radiator are hot. 
Serious injury, such as burns, may resu lt from hot coolant and steam released
under pressure.
Add coolant if necessary.
Water can be used in an emer-
gency measure if coolant is
unavailable. ( P. 5 4 8 )
Have the vehicle checked at your nearest Lexus dealer as soon as pos-
sible.
STEP6

586
Alphabetical index
GS_HV_U
December 12, 2007 3:50 pm
DoorsDoor lock................................ 35, 47, 50
Rear door child protector .................. 51
Driver’s seat belt reminder light .....493
Driver’s seat position memory ...........60
Driving Correct posture .................................... 93
Procedures .............................................128
DVD player/changer.......................... 266
Electric power steering ..................... 200
Electronic key If the electronic key does 
not operate properly ......................531
Replacing battery .............................. 454
Emergency, in case of If a warning light turns on ................491
If a warning message is displayed ........................................... 500
If the electronic key does 
not operate properly ......................531
If the hybrid system 
will not start .......................................528
If the shift lever cannot be  shifted from “P”................................ 529
If the 12 volt battery is 
discharged ....................................... 534
If you have a flat tire ............... 517, 527
If you lose your keys.........................530
If you think something is 
wrong .................................................. 488
If your vehicle becomes stuck.......541
If your vehicle needs to be 
towed ................................................... 482
If your vehicle overheats ................538
Energy monitor......................................... 27 Engine
ACCESSORY mode .....................139
Compartment ..................................... 420
Hood ......................................................... 417
How to start the 
hybrid system..................................... 138
If the hybrid system 
will not start ....................................... 528
Overheating ........................................ 538
Power (ignition) switch .................... 138
Engine compartment cover ............... 421
Engine coolant temperature 
gauge ...................................................... 148
Engine/power control unit coolant Capacity ................................................ 548
Checking................................................ 427
Preparing and checking 
before winter...................................... 215
Engine oil Capacity .................................................547
Checking................................................ 422
Preparing and checking 
before winter...................................... 215
Engine oil maintenance data ........... 425
Event data recorder ............................ 489
First-aid kit storage belt ..................... 375
Floor mats ................................................ 374
Fluid Brake ........................................................429
Washer....................................................434
Fog lights Switch .......................................................... 161
Wattage ................................................. 552
Foot light .................................................. 352
E
F

594
GS_HV_U
December 12, 2007 3:50 pm
What to do if...
What to do if...
A tire puncturesP. 5 1 7 /527If you have a flat tire
The hybrid system does not start
P. 8 8Immobilizer system
P. 5 2 8If the hybrid system will not start
P. 5 3 4If the 12 volt battery is discharged
The shift lever cannot be 
moved outP. 5 2 9If the shift lever cannot be shifted 
from “P”
The engine coolant temperature
gauge enters the red zone
Steam can be seen coming 
from under the hood
P. 5 3 8If your vehicle overheats
The key is lostP. 5 3 0If you lose your keys
The battery runs outP. 5 3 4If the 12 volt battery is discharged
The doors cannot be lockedP. 5 0Doors
The horn begins to soundP. 9 0Alarm
The vehicle is stuck in mud or
sandP. 5 4 1If the vehicle becomes stuck