Page 770 of 1014

7466-3. Do-it-yourself maintenance
GS450h_300h_OM_OM30D53E_(EE)
Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality eth-
ylene glycol based non-silicate, non-amine, non-nitrite, and non-borate cool-
ant with long-life hybrid organic acid technology.
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50%
deionized water. (Minimum temperature: -35C [-31F])
For more details about coolant, contact any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit coolant reser-
voir caps, drain cock and water pump.
If you cannot find a leak, have any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional, test the cap and check for
leaks in the cooling system.
CAUTION
When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps or the
coolant inlet cap. (P. 9 2 1 )
The cooling system may be under pressure and may spray hot coolant if the
cap is removed, causing serious injuries, such as burns.
NOTICE
When adding coolant
Coolant is neither plain water nor straight antifreeze. The correct mixture of
water and antifreeze must be used to provide proper lubrication, corrosion
protection and cooling. Be sure to read the antifreeze or coolant label.
If you spill coolant
Be sure to wash it off with water to prevent it from damaging parts or paint.
Page 856 of 1014

829
7 7-2. Steps to take in an emergency
When trouble arises
GS450h_300h_OM_OM30D53E_(EE)
If you think something is wrong
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.
Changes in exhaust sound
Excessive tire squeal when cornering
Strange noises related to the suspension system
Pinging or other noises related to the hybrid system
Engine missing, stumbling or running roughly
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
If you notice any of the following symptoms, your vehicle proba-
bly needs adjustment or repair. Contact any authorized Lexus
dealer or repairer, or another duly qualified and equipped profes-
sional as soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms
Page 945 of 1014
9187-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
After the hybrid system has cooled down sufficiently, inspect
the hoses and cooling system for leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immediately contact your Lexus
dealer.
The coolant level is satisfactory if it is between the “FULL”
and “LOW” lines on the reservoir.
Reservoir
“FULL”
“LOW”
Coolant inlet cap
3
1
2
GS300hGS450h
4
1
2
3
4
GS300hGS450h
Page 947 of 1014
9207-2. Steps to take in an emergency
GS450h_300h_OM_OM30D53E_(EE)
If “Hybrid System Overheat” is shown on the multi-information
display
Stop the vehicle in a safe place.
Stop the hybrid system and carefully lift the hood.
After the hybrid system has cooled down, inspect the hoses
and radiator core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immediately contact your Lexus
dealer.
The coolant level is satisfactory if it is between the “F”/
“FULL” and “L”/“LOW” lines on the reservoir.
Reservoir
“F”/“FULL”
“L”/“LOW”
1
2
3
1
2
GS300hGS450h
4
1
2
3
GS300hGS450h
Page 1000 of 1014

968Alphabetical index
GS450h_300h_OM_OM30D53E_(EE)
Emergency brake signal ............399
Emergency flashers ...................820
Emergency tire puncture
repair kit ..................................885
Energy monitor..........................131
Engine .......................................928
Accessory mode....................247
Compartment ........................738
Engine switch .......................246
Hood .....................................734
How to start the hybrid
system.................................246
Identification number ...........928
Ignition switch
(power switch)....................246
Overheating ..........................917
Power switch ........................246
Engine compartment cover........740
Engine coolant ...........................744
Capacity ................................933
Checking ...............................744
Preparing and checking
before winter ......................434
Engine coolant temperature
gauge .......................................109
Engine oil ..................................741
Capacity ................................930
Checking ...............................741
Oil level warning message....853
Oil pressure warning
message ..............................841
Preparing and checking
before winter ......................434Engine switch ........................... 246
EPS (Electric Power Steering) . 398
Function ............................... 398
Warning light ....................... 833
Warning message................. 845
EV drive mode.......................... 254
First-aid kit storage net ............. 694
Flat tire
Vehicles with a spare tire..... 871
Vehicles without a spare tire 885
Floor mats ................................... 34
Fluid
Brake.................................... 935
Hybrid transmission............. 934
Washer ................................. 748
Fog lights .................................. 283
Replacing light bulbs ... 805, 818
Switch .................................. 283
Wattage ................................ 940
Follow me home system ........... 273
Footwell light ........................... 684
Front air conditioning system ... 478
Front fog lights ......................... 283
Replacing light bulbs ... 805, 818
Switch .................................. 283
Wattage ................................ 940
Front personal lights ................. 685
Front position lights.................. 272
Light switch ......................... 272
Replacing light bulbs ........... 818
Welcome light illumination
control ............................... 143
F