2010 Lexus GS450h engine coolant

5
When trouble arises
581
5-2. Steps to take in an emergency
GS_HV_U (OM30C81U)
October 13, 2015 12:41 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. Carefully lift the hood after the
steam subsides and then restart the hybrid system.
If you do not see steam:
Leave the hybrid system operating and carefully lift the
hood.
Remove the engine compartment cover. (P. 4 6 1 )
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 immediately and call your 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

582
5-2. Steps to take in an emergency
GS_HV_U (OM30C81U)
October 13, 2015 12:41 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 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 hybrid
system is operating.
●Do not loosen the radiator cap while the hybrid system 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 3 )
Have the vehicle checked at your nearest Lexus dealer as soon as pos-
sible.
STEP6

593
6-1. Specifications
6
Vehicle specifications
GS_HV_U (OM30C81U)
February 1, 2010 11:10 am
Cooling system
Ignition system
Capacity
Gasoline engine
Power control unit9.8 qt. (9.3 L, 8.1 Imp.qt.)
3.0 qt. (2.9 L, 2.5 Imp.qt.)
Coolant type
Use either of the following:
• “Toyota Super Long Life Coolant”
• Similar high-quality ethylene glycol-based non-sili-
cate, non-amine, non-nitrite, and non-borate cool-
ant with long-life hybrid organic acid technology
Do not use plain water alone.
Spark plug
Make DENSOFK20HBR11
Gap0.043 in. (1.1 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust gap when tuning engine.

608
6-1. Specifications
GS_HV_U (OM30C81U)
February 1, 2010 11:10 am
Glossary of tire terminology
Tire related termMeaning
Cold tire inflation pres-
sureTire pressure when the vehicle has been parked for
three hours or more, or has not been driven more
than 1 mile or 1.5 km under that condition
Maximum inflation pres-
sureThe maximum cold inflated pressure to which a tire
may be inflated, shown on the sidewall of the tire
Recommended inflation
pressureCold tire inflation pressure recommended by a man-
ufacturer
Accessory weight
The combined weight (in excess of those standard
items which may be replaced) of transmission, power
steering, power brakes, power windows, power seats,
radio and heater, to the extent that these items are
available as factory-installed equipment (whether
installed or not)
Curb weight
The weight of a motor vehicle with standard equip-
ment, including the maximum capacity of fuel, oil and
coolant, and if so equipped, air conditioning and
additional weight optional engine
Maximum loaded vehicle
weight
The sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight
(d) Production options weight
Normal occupant weight150 lb. (68 kg) times the number of occupants speci-
fied in the second column of Table 1
* that follows
Occupant distributionDistribution of occupants in a vehicle as specified in
the third column of Table 1
* below

633
Alphabetical index
GS_HV_U (OM30C81U)
February 1, 2010 11:29 am
Engine compartment cover............... 461
Engine coolant temperature 
gauge ........................................................ 161
Engine/power control unit coolant
Capacity................................................. 593
Checking ............................................... 466
Preparing and checking 
before winter .................................... 233
Engine oil
Capacity...................................................591
Checking ............................................... 462
Preparing and checking 
before winter .................................... 233
Engine oil maintenance data ............464
Enhanced vehicle stability 
control .................................................... 214
Event data recorder............................ 532
First-aid kit storage belt....................... 421
Floor mats.................................................. 419
Fluid
Brake ....................................................... 468
Washer ....................................................474
Fog lights
Switch ........................................................ 174
Wattage ................................................. 597
Foot light .................................................. 395
Front passenger occupant 
classification system ........................... 119
Front passenger’s seat belt 
reminder light ......................................537
Front seats
Adjustment .............................................. 65
Driver’s seat position memory .......67
Front turn signal lights
Wattage ................................................. 597Fuel
Capacity ................................................ 590
Fuel gauge................................................ 161
Gas station information ..................644
Information ........................................... 598
Refueling.................................................... 94
Messages .............................................. 554
Fuel door ..................................................... 94
Fuel filler door ........................................... 94
Fuses .......................................................... 496
Garage door opener .......................... 423
Gas station information...................... 644
Gauges ........................................................ 161
Glove box ............................................... 400
Hands-free system
(for cellular phone) ..........................345
Head restraints ......................................... 72
Headlight aim ............................................511
Headlight cleaner .................................. 180
Headlights
Adaptive front lighting system....... 172
Discharge headlights 
precautions....................................... 520
Replacing light bulbs ......................... 514
Switch.......................................................... 171
Wattage ..................................................597
Heaters
Seat heaters ........................................... 413
Side mirror............................................ 268
Hill-start assist control ......................... 214
Hood .......................................................... 457
Hooks
Cargo ........................................................421
Shopping bag ........................................421
F
G
H

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GS_HV_U (OM30C81U)
February 1, 2010 11:14 am
What to do if...
What to do if...
A tire puncturesP. 5 6 0 /
570If you have a flat tire
The hybrid system does not start
P. 9 9Immobilizer system
P. 5 7 2If the hybrid system will not start
P. 5 7 8If the 12 volt battery is discharged
The shift lever cannot be 
moved outP. 5 7 3If 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 8 1If your vehicle overheats
The key is lostP. 5 74If you lose your keys
The 12 volt battery runs outP. 5 7 8If the 12 volt battery is discharged
The doors cannot be lockedP. 5 5Doors
The horn begins to soundP. 1 0 1Alarm
The vehicle is stuck in mud or
sandP. 5 8 4If the vehicle becomes stuck