2010 Lexus GS450h radiator

467
4-3. Do-it-yourself maintenance
4
Maintenance and care
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
CAUTION
■When the hybrid system is hot
Do not remove the radiator and reservoir cap.
The cooling system may be under pressure and may spray hot coolant if the cap is
removed, causing burns or other injuries.
NOTICE
■When adding the 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.

468
4-3. Do-it-yourself maintenance
GS_HV_U (OM30C81U)
October 13, 2015 12:41 pm
Radiator and condenser
Check the radiator and condenser and clear any foreign objects. 
If either of the above parts are extremely dirty or you are not sure of their
condition, have your vehicle checked by your Lexus dealer.
Brake fluid
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN”
lines on the tank.
Make sure to check the fluid type and prepare the necessary items.
■Adding fluid
CAUTION
■When the hybrid system is hot
Do not touch the radiator or condenser, as they may be hot and you may be burned.
Fluid typeFMVSS No.116 DOT 3 or SAE J1703 brake fluid
ItemsClean funnel

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

635
Alphabetical index
GS_HV_U (OM30C81U)
February 1, 2010 11:29 am
Mirrors
Inside rear view mirror ...................... 83
Side mirror heater ............................. 268
Side mirrors............................................. 85
Vanity mirrors ..................................... 407
Moon roof .................................................. 90
MP3 disc ................................................. 289
Multi-information display....................168
Noise from under the vehicle .............. 18
Odometer .................................................. 161
Oil
Engine oil ............................................... 462
Opener
Fuel filler door .........................................94
Hood ....................................................... 457
Trunk........................................................... 60
Outer foot lights ................................... 395
Outside rear view mirrors
Adjusting and folding ......................... 85
Mirror position memory ....................67
Outside temperature 
display .................................................... 409
Overhead console .............................. 402
Overheating, Engine ............................581Parking brake .......................................... 159
Parking lights
Replacing light bulbs ......................... 514
Switch.......................................................... 171
Wattage ..................................................597
Personal lights ........................................ 397
Portable music player .......................... 341
Power meter .............................................. 161
Power outlet............................................. 412
Power windows ........................................ 87
Power (ignition) switch........................ 150
Pre-collision system...............................221
Radar cruise control ............................. 185
Radiator ....................................................468
Radio .......................................................... 273
Radio data system ................................ 275
Rear sunshade ........................................ 416
Rear turn signal lights
Replacing light bulbs ......................... 514
Wattage ..................................................597
Rear view monitor system.................. 210
Rear window defogger ......................268
Replacing
Electronic key battery ......................494
Fuses........................................................ 496
Light bulbs .............................................. 514
Reporting safety defects for 
U.S. owners .......................................... 624
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