cooling Lexus HS250h 2010 Using the Bluetooth audio system / LEXUS 2010 HS250H (OM75006U) User Guide

5
When trouble arises
541
5-2. Steps to take in an emergency
If your vehicle overheats
Correction procedures
■If the engine coolant temperature warning light comes on or flashes
Stop the vehicle in a safe place an d turn of
f the air conditioning
system.
Check to see if steam is coming out from the engine area.
If you see steam: 
Stop the hybrid system. Carefu lly lif
t 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 2 3 )
Check to see if the cooling fans are operating.
If the fans are operating: 
Wait until the high engine coolant temperature warning light goes
of
f and then stop the hybrid system.
If the fans are not operating: 
Stop the hybrid system immediately and call your Lexus dealer.
The following may indicate that your vehicle is overheating:
●The high engine coolant temperature warning light comes on or
flashes: 
The engine may be overheating.
● “HYBRID S
YSTEM OVERHEAT” is sh own on the multi-information
display: 
The power control unit may be overheating.
Follow the correction procedure as described below.

542
5-2. Steps to take in an emergency
After the hybrid system has cooled
down sufficiently, check the engine
coolant level and inspect the cool-
ing system for leaks.
Add engine coolant if necessary.
Water can be used in an emer -
gency if engine coolant is unavail -
able. ( P. 5 5 2 )
Have the vehicle inspected at the ne arest Lexus dealer as soon as possi-
ble.
■ If “HYBRID S
YSTEM OVERHEAT” is shown on the multi-informa -
tion display
Stop the vehicle in a safe place an d turn of
f the air conditioning
system.
Leave the hybrid system operating and carefully lift the hood.
Remove the engine compartment covers. ( P. 4 2 3 )
Check if the cooling fans are operating.
If the fans are operating: 
Wait until the “HYBRID SYST EM O
VERHEAT” message disap-
pears and then stop the hybrid system. 
If the message does not disappear, call your Lexus dealer.
If the fans are not operating: 
Stop the hybrid system immediately and call your Lexus dealer.

5
When trouble arises
543
5-2. Steps to take in an emergency
After the hybrid system has cooled
down, check the power control
unit coolant level and inspect the
cooling system for leaks.
Add power control unit coolant if
nec
essary.
Water can be used in an emer -
gency if power control unit coolant
is una
vailable. ( P. 5 5 2 )
Have the vehicle inspected at the ne arest Lexus dealer as soon as possi-
ble.
■Overheating
The following symptoms may occur wh en
your vehicle is overheating:
●The high engine coolant temperature warn ing light comes on or flashes, or the
hybrid system output decreases.
●Steam comes out from the engine area.
●“HYBRID SYSTEM OVERHEAT” is displayed on the multi-information display.

544
5-2. Steps to take in an emergency
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 compartm ent may be very hot, causing serious
injuries such as burns.
●Check that the indicator on the “POWER ” switch and the READY indicator are
off.
●For vehicles with a hybrid system, there are times when the gasoline engine auto-
matically starts to run or the cooling fans suddenly start to operate. Do not touch
or approach the rotating parts of the belt or fans. Doing so may lead to fingers,
clothes or tools getting caught, resulting in injury.
●Do not loosen the coolant reservoir cap while the hybrid system and radiator are
hot. 
Serious injuries, such as burns, may resu lt from hot coolant and steam released
under pressure.
NOTICE
■When adding engine/power control unit coolant
Wait until the hybrid system has cooled down before adding engine/power control
unit coolant. 
When adding coolant, do so slowly. Adding cool coolant to a hot hybrid system too
quickly can cause damage to the hybrid system.

552
6-1. Specifications
Cooling system
Ignition system
CapacityGasoline engine
Power control unit
7.7 qt. (7.3 L, 6.4 Imp. qt.)
3.1 qt. (2.9 L, 2.6 Imp. qt.)
Coolant type
Use either of the following.• “Toyota Super Long Life Coolant”
• A similar high-quality ethylene glycol-
based non-silicate, non-amine, non-nitrite,
and non-borate coolant with long-life
hybrid organic acid technology
Do not use plain water alone.
Spark plug
Make 

GapDENSO SK20R11 
NGK IFR6A11 
0.043 in. (1.1 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust spark plug gap.

594
Alphabetical index
Child-protectors ......................................58
CleaningExterior ................................................... 402
Interior .....................................................406
Seat belts................................................ 407
Clock ......................................................... 373
Coin holder .............................................366
Compass ................................................... 391
Condenser ..............................................430
Console box ...........................................365
Cooling system Engine overheating ............................541
Cruise control Cruise control .......................................201
Dynamic radar cruise control .....205
Cup holders ............................................ 367
Curtain shield airbags.......................... 103
Customizable features ....................... 572
Daytime running light system ........... 186
Defogger Rear window ........................................260
Side mirrors ..........................................260
Dimensions............................................. 548
Dinghy towing ........................................248 Display
Dynamic radar cruise 
control ................................................. 205
Multi-information display ................ 169
Trip information.....................................172
Warning message ..............................501
Do-it-yourself maintenance ...............416
Door courtesy lights Door courtesy lights ........................ 360
Wattage ................................................. 556
Doors Door glasses........................................... 86
Door lock ................................ 44, 54, 57
Rear door child protector................ 58
Side doors................................................. 57
Side mirrors............................................. 83
Driver’s seat belt reminder light ..... 495
Driver’s seat position memory ........... 68
Driving Break-in tips........................................... 137
Correct posture.....................................101
Procedures............................................. 136
Winter driving tips .............................244
Driving position memory...................... 68
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