Page 572 of 660

5727-2. Steps to take in an emergency
RX450h_U_OM0E013U
WARNING
■Avoiding 12-volt battery fires or explosions
Observe the following precautions to prevent accidentally igniting the flammable gas
that may be emitted from the 12-volt battery:
●Make sure each jumper cable is connected to the correct terminal and that it is not
unintentionally in contact with any other than the intended terminal.
●Do not allow the other end of the jumper cab le connected to the “+” terminal to come
into contact with any other parts or metal surfaces in the area, such as brackets or
unpainted metal.
●Do not allow the + and - clamps of the jumper cables to come in to contact with each
other.
●Do not smoke, use matches, cigarette light ers or allow open flame near the 12-volt
battery.
■12-volt battery precautions
The 12-volt battery contains poisonous and co rrosive acidic electrolyte, while related
parts contain lead and lead compounds. Ob serve the following precautions when han-
dling the 12-volt battery:
●When working with the 12-volt battery, always wear safety glasses and take care not
to allow any battery fluids (acid) to come in to contact with skin, clothing or the vehicle
body.
●Do not lean over the 12-volt battery.
●In the event that battery fluid comes into contact with the skin or eyes, immediately
wash the affected area with water and seek medical attention.
Place a wet sponge or cloth over the affected area until medical attention can be
received.
●Always wash your hands after handling the 12-volt battery support, terminals, and
other battery-related parts.
●Do not allow children near the 12-volt battery.
■After recharging the 12-volt battery
Have the 12-volt battery inspected at yo ur Lexus dealer as soon as possible.
If the 12-volt battery is deteriorating, continued use may cause the 12-volt battery to
emit a malodorous gas, which may be de trimental to the health of passengers.
■When exchanging the 12-volt battery
After exchanging, securely attach the exhaust hose and exhaust hole plug to the
exhaust hole of the exchanged 12-volt batter y. If not properly installed, gases (hydro-
gen) may leak into the vehicle interior, and there is the possible danger of the gas ignit-
ing and exploding.
Page 574 of 660

5747-2. Steps to take in an emergency
RX450h_U_OM0E013U
■“Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” is
shown on the multi-information displayStop the vehicle in a safe place and turn off the air conditioning system, 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 radiator core (radi-
ator) 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” line
“LOW” line
Radiator cap
If your vehicle overheats
The following may indicate that your vehicle is overheating.
●The needle of the engine coolant temperature gauge ( P. 97) enters the
red zone, or a loss of hybrid system power is experienced. (For example, the
vehicle speed does not increase.)
●“Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” or
“Hybrid System Overheated Reduced Output Power” is shown on the
multi-information display.
●Steam comes out from under the hood.
Correction procedures
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Page 575 of 660

5757-2. Steps to take in an emergency
7
When trouble arises
RX450h_U_OM0E013U
Add coolant if necessary.
Water can be used in an emergency
if coolant is unavailable.
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, tu rn the air conditioning system on and off
repeatedly. (The fans may not operate in freezing temperatures.)
If the fans are not operating:
Stop the hybrid system immediately and contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the nearest Lexus dealer.
Check if “Engine Coolant Temp High Stop in a Safe Place See Owner’s
Manual” is shown on the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer.
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Page 576 of 660
5767-2. Steps to take in an emergency
RX450h_U_OM0E013U
■If “Hybrid System Overheated Reduced Output Power” is shown on the
multi-information displayStop the vehicle in a safe place.
Stop the hybrid system an d 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 “FULL” and
“LOW” lines on the reservoir.Reservoir
“FULL” line
“LOW” line
Add coolant if necessary.
Water can be used in an emergency
if coolant is unavailable.
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Page 577 of 660

5777-2. Steps to take in an emergency
7
When trouble arises
RX450h_U_OM0E013U
Start the hybrid system and check if “Hybrid System Overheated Reduced
Output Power” is shown on the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer.
WARNING
■To prevent an accident or injury 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 h ood, 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 “READY” indicator is off.
When the hybrid system is operating, the gasoline engine may automatically start, or
the cooling fans may suddenly operate even if the gasoline engine stops. Do not
touch or approach rotating parts such as th e fans, which may lead to fingers or cloth-
ing (especially a tie, a scarf or a muffler) getting caught, resulting in serious injury.
●Do not loosen the radiator cap and the coolant reservoir caps wh ile the hybrid system
and radiator are hot.
High temperature steam or coolant could spray out.
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 foreig n matter (such as sand or dust etc.).
●Do not use any coolant additive.
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Page 578 of 660
5787-2. Steps to take in an emergency
RX450h_U_OM0E013U
Stop the hybrid system. Shift the shift lever to P and set the parking brake.
Remove the mud, snow or sand from around the front wheels.
Place wood, stones or some other materi al under the front wheels to help pro-
vide traction.
Restart the hybrid system.
Shift the shift lever to D or R and rele ase the parking brake. Then, while exer-
cising caution, depress the accelerator pedal.
■When it is difficult to free the vehicle
If the vehicle becomes stuck
Carry out the following procedures if the tires spin or the vehicle becomes
stuck in mud, dirt or snow:
Press to turn off TRAC.
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Page 586 of 660

5868-1. Specifications
RX450h_U_OM0E013U
■Engine oil selection
“Toyota Genuine Motor Oil” is used in your Lexus vehicle. Use Lexus
approved “Toyota Genuine Motor Oil” or equivalent to satisfy the following
grade and viscosity.
Oil grade: ILSAC GF-5 multigrade engine oil
Recommended viscosity: SAE 0W-20
SAE 0W-20 is the best choice for
good fuel economy and good start-
ing in cold weather.
If SAE 0W-20 is not available, SAE
5W-20 oil may be used. However, it
must be replaced with SAE 0W-20
at the next oil change.
Oil viscosity (0W-20 is explained here as an example):
• The 0W in 0W-20 indicates the characteristic of the oil which allows cold startability. Oils with a lower value be fore the W allow for easier starting of
the engine in cold weather.
• The 20 in 0W-20 indicates the viscos ity characteristic of the oil when the
oil is at high temperature. An oil with a higher viscosity (one with a higher
value) may be better suited if the vehicle is operated at high speeds, or
under extreme lo ad conditions.
How to read oil container label:
The International Lubricant Specifi-
cation Advisory Committee
(ILSAC) Certification Mark is added
to some oil containers to help you
select the oil you should use.
Outside temperature
Page 587 of 660

5878-1. Specifications
8
Vehicle specifications
RX450h_U_OM0E013U
*: The coolant capacity is a reference quantity. If replacement is necessary, contact your Lexus dealer.
Cooling system
Capacity*
Gasoline engine
10.7 qt. (10.1 L, 8.9 Imp. qt.)
Power control unit
2.0 qt. (1.9 L, 1.7 Imp. qt.)
Coolant type
Use either of the following: • “Toyota Super Long Life Coolant”
• 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.
Ignition system (spark plug)
MakeDENSO FK20HBR8
Gap0.03 in. (0.8 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.
Electrical system
12-volt battery
Open voltage at 68F (20 C):
12.6 V or higher: Fully charged
12.2 — 12.4 V: Half charged
12.0 V or lower: Discharged
(Voltage is checked 20 minutes after the hybrid
system and all lights are turned off.)
Charging rates5 A max.