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GS450h_OM_OM30F70U_(U)
4356-3. Do-it-yourself maintenance
6
Maintenance and care
■Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high quality ethylene glycol
based non-silicate, non-amine, non-nitrite, and non-borate coolant with long-life
hybrid organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deionized
water. (Minimum temperature: -31 °F [-35 °C])
Canada:
“Toyota Super Long Life Coolant” is a mixture of 55% coolant and 45% deionized
water. (Minimum temperature: -44 °F [-42 °C])
For more details about coolant, contact your Lexus dealer.
■If the coolant level drops within a short time of replenishing
Visually check the radiator, hoses, engine/power control unit coolant reservoir caps,
drain cock and water pump.
If you cannot find a leak, have your Lexus dealer 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 cool-
ant inlet cap. ( →P. 5 7 0 )
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.
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Page 437 of 654
436
GS450h_OM_OM30F70U_(U)
6-3. Do-it-yourself maintenance
Check the radiator and condenser and clear away any foreign objects.
If either of the above parts is extremely dirty or you are not sure of their
condition, have your vehicle inspected by your Lexus dealer.
Radiator and condenser
CAUTION
■When the hybrid system is hot
Do not touch the radiator or condenser as they may be hot and cause serious inju-
ries, such as burns.
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Page 567 of 654

566
GS450h_OM_OM30F70U_(U)
7-2. Steps to take in an emergency
If your vehicle overheats
■If the needle of the engine coolant temperature gauge enters the red
zone
Stop the vehicle in a safe place and turn off the air conditioning sys-
tem, and then stop the hybrid system.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
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 following may indicate that your vehicle is overheating.
●The needle of the engine coolant temperature gauge ( →P. 91) enters
the red zone or a loss of hybrid system power is experienced. (For
example, the vehicle speed does not increase.)
●“Hybrid System Overheat” ( →P. 527) is shown on the multi-informa-
tion display.
●Steam comes out from under the hood.
Correction procedures
1
2
3
1
2
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5677-2. Steps to take in an emergency
GS450h_OM_OM30F70U_(U)
7
When trouble arises
The coolant level is satisfactory if it is between the “FULL” and
“LOW” lines on the reservoir.Reservoir
“FULL”
“LOW”
Coolant inlet cap
Add coolant if necessary.
(→ P. 569)
Water can be used in an emer-
gency if engine coolant is unavail-
able.
Start the hybrid system and turn the air conditioning system on to
check that the radiator cooling fans operate and to check for coolant
leaks from the radiator or hoses.
The fans operate when the air conditioning system is turned on immediately
after a cold start. Confirm that the fans are operating by checking the fan
sound and air flow. If it is difficult to check these, turn the air conditioning sys-
tem on and off repeatedly. (The fans may not operate in freezing tempera-
tures.)
If the fans are not operating:
Stop the hybrid system immediatel y and contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the nearest Lexus dealer.
4
1
2
3
4
5
6
7
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5687-2. Steps to take in an emergency
GS450h_OM_OM30F70U_(U)
■If “Hybrid System Overheat” is shown on the multi-information dis-
play
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 radi-
ator 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 “FULL” and
“LOW” lines on the reservoir.Reservoir
“FULL”
“LOW”
Add coolant if necessary.
Water can be used in an emer-
gency if power control unit coolant
is unavailable.
1
2
3
1
2
4
1
2
3
5
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Page 571 of 654

5707-2. Steps to take in an emergency
GS450h_OM_OM30F70U_(U)
CAUTION
■When inspecting under the hood of your vehicle
Observe the following precautions.
Failure to do so may result in serious injury such as burns.
●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.
●After the hybrid system has been turned off, check that the indicator on the
power switch and the “READY” indicator are off.
When the hybrid system is operating, the gasoline engine may automatically
start, or the cooling fan may suddenly operate even if the gasoline engine stops.
Do not touch or approach rotating parts such as the fan, which may lead to fin-
gers or clothing (especially a tie, a scarf or a muffler) getting caught, resulting in
serious injury.
NOTICE
■When adding engine/power control unit coolant
Add coolant slowly after the hybrid system has cooled down sufficiently. Adding
cool coolant to a hot hybrid system too quickly can cause damage to the hybrid
system.
■To prevent damage to the cooling system
Observe the following precautions:
●Avoid contaminating the coolant with foreign matter (such as sand or dust etc.).
●Do not use any coolant additives.
●Do not loosen the coolant inlet cap or the
coolant reservoir cap while the hybrid sys-
tem and radiator are hot.
High temperature steam or coolant could
spray out.
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Page 646 of 654

645Alphabetical index
GS450h_OM_OM30F70U_(U)
Pre-Collision System (PCS) ............ 290Function ................................................. 290
PCS OFF switch ................................ 292
Warning light ...................................... 505
Warning message .......................515, 526, 532
Radar cruise control (dynamic radar cruise control) ........................ 239
Radiator .................................................... 436
Radio
*
RBDS (Radio Broadcast Data Systems)
*
Rear air conditioning system ........... 355
Rear door sunshades ..........................388
Rear personal lights............................. 364
Rear side marker lights ........................ 217
Light switch ............................................. 217
Replacing light bulbs ....................... 489
Welcome light illumination control ..........................123
Rear seat heaters.................................. 382
Rear sunshade ....................................... 387 Operation ..............................................387
Reverse operation feature............ 388 Rear turn signal lights ......................... 209
Replacing light bulbs ....................... 487
Turn signal lever ................................. 209
Wattage .................................................583
Rear view mirror Inside rear view mirror...................... 162
Outside rear view mirrors ..............164
Rear view monitor system
*
Rear window defoggers.................... 360
Refueling.................................................. 230
Capacity ................................................. 576
Fuel types............................................... 576
Opening the fuel tank cap ............ 232
When the fuel filler door cannot be opened ......................... 233
Regenerative braking............................. 74
Remote Touch
*.....................................326
Replacing
Electronic key battery .....................460
Fuses ........................................................ 462
Light bulbs............................................. 479
Tires ............................................................541
Reporting safety defects for U.S. owners .................................... 612
Resetting the message indicating maintenance is required .................. 416
Road accident cautions ......................... 79
R
*: Refer to the “NAVIGATION AND MULTIMEDIA SYSTEM OWNER’S MANUAL”.
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