2010 Lexus GS350 coolant temperature

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2
When driving
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
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
“ENGINE START STOP” switch is in IGNITION ON mode.
Tachometer
Displays the engine speed in revolutions per minute.
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 4

150
2-2. Instrument cluster
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
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 7 8 )
●Do not let the indicator needle of the tachometer enter the red zone, which indi-
cates the maximum engine speed.
■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.

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4-3. Do-it-yourself maintenance
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
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, radiator, exhaust manifold, etc. right after driv-
ing 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 or the 12 volt battery.
Fuel and 12 volt battery fumes are flammable.
●Be extremely cautious when working on the 12 volt battery. It contains poisonous
and corrosive sulfuric acid.
■When working near the electric cooling fan or radiator grille
Be sure the “ENGINE START STOP” switch is OFF.
With the “ENGINE START STOP” switch in IGNITION 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 5 7 )
■Safety glasses
Wear safety glasses to prevent flying or falling 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.

530
5-1. Essential information
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
If you think something is wrong
If you notice any of the following symptoms, your vehicle probably needs
adjustment or repair. Contact your Lexus dealer as soon as possible.
■Visible symptoms
●Fluid leaks under the vehicle
(Water dripping from the air conditioning after use is normal.)
●Flat-looking tires or uneven tire wear
●Engine coolant temperature gauge needle continually points
higher than normal
■Audible symptoms
●Changes in exhaust sound
●Excessive tire squeal when cornering
●Strange noises related to the suspension system
●Pinging or other noises related to the engine
■Operational symptoms
●Engine missing, stumbling or running rough
●Appreciable loss of power
●Vehicle pulls heavily to one side when braking
●Vehicle pulls heavily to one side when driving on a level road
●Loss of brake effectiveness, spongy feeling, pedal almost touches
the floor

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5-2. Steps to take in an emergency
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
If your vehicle overheats
If your engine 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 engine. Carefully lift the hood after the steam sub-
sides and then restart the engine.
If you do not see steam:
Leave the engine running and carefully lift the hood.
Remove the engine compartment cover. (P. 450)
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 engine.
If the fan is not operating: 
Stop the engine immediately and call your Lexus dealer.
After the engine 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
579
5-2. Steps to take in an emergency
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
■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.
CAUTION
■To prevent an accident or injury when inspecting under the hood of your vehicle
●If steam is seen coming from under the hood, do not open the hood until the
steam has subsided. The engine compartment may be very hot, causing serious
injury such as burns.
●Keep hands and clothing away from the fan and engine drive belt while the
engine is running.
●Do not loosen the radiator cap while the engine and radiator are hot.
Serious injury, such as burns, may result 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 9 4 )
Have the vehicle checked at your nearest Lexus dealer as soon as pos-
sible.
STEP6

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Alphabetical index
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
Daytime running light system ........... 158
Defogger
Rear window ........................................ 255
Side mirror ............................................ 255
Dimension ............................................... 586
Dinghy towing ........................................ 225
Display
Multi-information display.................154
Touch screen ....................................... 228
Trip information ................................... 155
Warning message............................. 543
Do-it-yourself maintenance ............. 442
Door courtesy lights ............................382
Door pocket............................................ 392
Doors
Door lock...................................29, 41, 43
Rear door child protector ................ 44
Driver’s seat belt reminder light .....536
Driver’s seat position memory ...........55
Driving
Correct posture ...................................... 91
Procedures ............................................. 126
DVD player/changer......................... 280
Electric power steering ..................... 200
Electronic key
If the electronic key does 
not operate properly ...................... 571
Replacing battery .............................. 482Emergency, in case of
If a warning light turns on .............. 534
If a warning message is 
displayed ............................................ 543
If the electronic key does 
not operate properly ..................... 571
If the engine will not 
start .......................................................568
If the shift lever cannot be 
shifted from “P” ............................... 569
If the 12 volt battery is 
discharged ........................................574
If you have a flat tire ........... 556, 566
If you lose your keys ........................ 570
If you think something is 
wrong .................................................. 530
If your vehicle becomes stuck ......581
If your vehicle has to be stopped 
in an emergency ............................ 583
If your vehicle needs to be 
towed ................................................... 520
If your vehicle overheats................ 578
Engine
ACCESSORY mode....................... 136
Compartment ..................................... 448
Engine (ignition) switch.................... 135
Hood ....................................................... 445
How to start the engine ................... 135
If the engine will not start ...............568
Overheating ........................................ 578
Engine compartment cover ............. 450
Engine coolant temperature 
gauge ....................................................... 147D
E

642
GS_G_U (OM30C80U)
June 29, 2011 10:30 am
What to do if...
What to do if...
A tire puncturesP. 5 5 6 /
566If you have a flat tire
The engine does not start
P. 8 5Immobilizer system
P. 5 6 8If the engine will not start
P. 5 74If the 12 volt battery is discharged
The shift lever cannot be 
moved outP. 5 6 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 7 8If your vehicle overheats
The key is lostP. 5 7 0If you lose your keys
The 12 volt battery runs outP. 5 74If the 12 volt battery is discharged
The doors cannot be lockedP. 4 3Doors
The horn begins to soundP. 8 7Alarm
The vehicle is stuck in mud or
sandP. 5 8 1If the vehicle becomes stuck