2021 LEXUS NX300h coolant temperature

3536-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manual_USA_M78578_en
6
Maintenance and care
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN” lines
on the tank.
■Adding fluid
Make sure to check the fluid type and
prepare the necessary item.
 Fluid type
FMVSS No.116 DOT 3 or SAE J1703;
FMVSS No.116 DOT 4 or SAE J1704
brake fluid
Items
Clean funnel
■Brake fluid can absorb moisture from
the air
Excess moisture in the brake fluid can cause a dangerous loss of braking efficiency. Use
only newly opened brake fluid.
If none of the washer do not work or
the “Windshield Washer Fluid Low” on
the multi-information display, the
washer tank may be empty. Add
washer fluid.
WARNING
■When the electric cooling fans are
operating
Do not touch the engine compartment.
With the power switch in ON mode, the
electric cooling fans may automatically
start to run if the air conditioning is on
and/or the coolant temperature is high.
Be sure the power switch is off when
working near the electric cooling fans or
radiator grille.
Checking and adding the brake
fluid
WARNING
■When filling the reservoir
Take care as brake fluid can harm your
hands and eyes and damage painted sur-
faces.
If fluid gets on your hands or in your eyes,
flush the affected area with clean water
immediately.
If you still experience discomfort, see a
doctor.
NOTICE
■If the fluid level is low or high
It is normal for the brake fluid level to go
down slightly as the brake pads wear out
or when the fluid leve l in the accumulator
is high.
If the reservoir needs frequent refilling,
there may be a serious problem.
Checking and adding the washer
fluid

3867-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
4Tighten down the towing eyelet
securely using a wheel nut wrench
or hard metal bar.
5 Securely attach cables or chains to
the towing eyelet.
Take care not to damage the vehicle body.
6Enter the vehicle being towed and
start the hybrid system.
If the hybrid system does not start, turn the
power switch to ON mode.
7Shift the shift lever to N and release
the parking brake.
Turn automatic mode off. ( P.184)
When the shift lever cannot be shifted:
 P.181
■While towing
If the hybrid system is off, the power assist
for the brakes and steering will not function,
making steering and braking more difficult.
■Wheel nut wrench
Wheel nut wrench is installed in luggage
compartment. ( P.402)
 Fluid leaks under the vehicle
(Water dripping from the air condi-
tioning 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 corner-
ing
 Strange noises related to the sus-
pension system
 Pinging or other noises related to
the hybrid system
 Engine misfire or misses, stumbling
or running roughly
 Appreciable loss of power
 Vehicle pulls heavily to one side
when braking
If you think something is
wrong
If you notice any of the following
symptoms, your vehicle probably
needs adjustment or repair. Con-
tact your Lexus dealer as soon as
possible.
Visible symptoms
Audible symptoms
Operational symptoms

3897-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
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When trouble arises
■Low engine oil pressure warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
■High coolant temperature warning light* (warning buzzer)
*: This light illuminates on the multi-information display.
■Brake system warning light
■Malfunction indicator lamp
Warning lightDetails/Actions
Indicates that the engine oil pressure is too low
Immediately stop the vehicl e in a safe place and con-
tact your Lexus dealer. Continuing to drive the vehicle
may be dangerous.
Warning lightDetails/Actions
Indicates that the engine is overheating
 Immediately stop the vehicle in a safe place. Continu-
ing to drive the vehicle may be dangerous.
Handling method ( P.418)
Warning lightDetails/Actions
(Yellow)
Indicates a malfunction in:
The regenerative braking system;
 The electronically controlled brake system; or
 The electric parking brake
 Have the vehicle inspected by your Lexus dealer
immediately.
Warning lightDetails/Actions
(U.S.A.)
(Canada)
Indicates a malfunction in:
 The hybrid system;
 The electronic engine control system;
 The electronic throttle control system; or
 The emission control system
 Have the vehicle inspected by your Lexus dealer
immediately.

4187-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
■“Engine Coolant Temp High” is
shown on the multi-information dis-
play
1 Stop the vehicle in a safe place and
turn off the air conditioning system,
and then stop the hybrid system.
2 If you see steam:
Carefully lift the hood after the
steam subsides.
If you do not see steam:
Carefully lift the hood.
3 After the hybrid system has cooled
down sufficiently, inspect the hoses
WARNING
●Do not allow children near the 12-volt
battery.
■After recharging the 12-volt battery
Have the 12-volt battery inspected at
your Lexus dealer as soon as possible.
If the 12-volt battery is deteriorating, con-
tinued use may cause the 12-volt battery
to emit a malodorous gas, which may be
detrimental 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 battery. If not properly installed,
gases (hydrogen) may leak into the vehi-
cle interior, and there is the possible dan-
ger of the gas igniting and exploding.
NOTICE
■When handling jumper cables
When connecting the jumper cables,
ensure that they do not become entan-
gled in the cooling fans or belt.
■To prevent damaging the vehicle
The exclusive jump starting terminal is to
be used when charging the 12-volt bat-
tery from another ve hicle in an emer-
gency. It cannot be used to jump start
another vehicle.
If your vehicle overheats
The following may indicate that
your vehicle is overheating.
 The needle of the engine coolant
temperature gauge ( P.84)
enters the red zone, or a loss of
hybrid system power is experi-
enced. (For example, the vehicle
speed does not increase.)
 “Engine Coolant Temp High” or
“Hybrid System Overheated” is
shown on the multi-information
display.
 Steam comes out from under the
hood.
Correction procedures

4207-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
■If “Hybrid System Overheated” is
shown on the multi-information dis-
play
1 Stop the vehicle in a safe place.
2 Stop the hybrid system and care-
fully lift the hood.
3 After the hybrid system has cooled
down, inspect the hoses and radia-
tor core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4The coolant level is satisfactory if it
is between the “FULL” and “LOW”
lines on the reservoir.
Reservoir
“FULL” line
“LOW” line 5
Add coolant if necessary.
Water can be used in an emergency if
coolant is unavailable.
6After stopping the hybrid system
and waiting for 5 minutes or more,
start the hybrid system again and
check if “Hybrid System Over-
heated” is shown on the multi-infor-
mation display.
If the message does not disappear:
Stop the hybrid system and contact your
Lexus dealer.
If the message is not displayed:
The hybrid system temperature has
dropped and the vehicle may be driven
normally.
However, if the message appears again fre-
quently, contact your Lexus dealer.
A
B
A
B
C
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
hood, do not open the hood until the
steam has subsided. The engine com-
partment may be very hot.

4217-2. Steps to take in an emergency
LEXUS NX300h Owners Manual_USA_M78578_en
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When trouble arises
1Stop the hybrid system. Shift the
shift lever to P and set the parking
brake.
2 Remove the mud, snow or sand
from around the front wheels.
3 Place wood, stones or some other
material under the front wheels to
help provide traction.
4 Restart the hybrid system.
5 Shift the shift lever to D or R,
release the parking brake. Then,
while exercising caution, depress
the accelerator pedal.
■When it is difficult to free the vehicle
Press to turn off TRAC. ( P.273)
WARNING
●After the hybrid system has been
turned off, check that the “READY”
indicator is off. When the hybrid sys-
tem 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 fingers or cloth-
ing (especially a tie, a scarf or a muf-
fler) getting caught, resulting in serious
injury.
●Do not loosen the coolant reservoir
cap while the hybrid system and radia-
tor are hot.
High temperature steam or coolant
could spray out.
NOTICE
■When adding engine/power control
unit coolant
Add coolant slowly after the hybrid sys-
tem 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 sys-
tem
Observe the following precautions:
●Avoid contaminating the coolant with
foreign matter (such as sand or dust
etc.).
●Do not use any coolant additive.
If the vehicle becomes stuck
Carry out the following proce-
dures if the tires spin or the vehicle
becomes stuck in mud, dirt or snow:
Recovering procedure

4278-1. Specifications
LEXUS NX300h Owners Manual_USA_M78578_en
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Vehicle specifications
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.
Outside temperature
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 before the W allow for easier
starting of the engine in cold
weather. • The 20 in 0W-20 indicates the vis-
cosity 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 load con-
ditions.
How to read oil container label:
The International Lubricant Specifica-
tion Advisory Committee (ILSAC)
Certification Mark is added to some oil
containers to help you select the oil you
should use.
A
Cooling system
Capacity*
Gasoline
engine
Vehicles with towing package
7.7 qt. (7.3 L, 6.4 Imp.qt.)
Vehicles without towing package
7.1 qt. (6.7 L, 5.9 Imp.qt.)
Power con-
trol unit3.3 qt. (3.1 L, 2.7 Imp.qt.)
Coolant type
Use either of the following:
 “Toyota Super Long Life Coolant”
 Similar high-quality ethy lene glycol-based non-
silicate, non-amine, non-nitrite, and nonborate
coolant with long-life hy brid organic acid tech-
nology
Do not use plain water alone.

474Alphabetical Index
LEXUS NX300h Owners Manual_USA_M78578_en
Replacing the battery...............................369
Electronically Controlled Brake System (ECB) .............................................................272
Emergency flashers ....................................380
Emergency, in case of If a warning buzzer sounds ................. 388
If a warning light turns on ..................... 388
If a warning message is displayed.....398
If the 12-volt battery is discharged ...... 414
If the electronic key does not operate properly......................................................... 412
If the fuel filler door cannot be opened .............................................................................411
If the hybrid system will not start ........409
If the vehicle is trapped in rising water .......................................................................... 381
If you have a flat tire .................................. 402
If you lose your keys.....................................411
If you think something is wrong .........386
If your vehicle becomes stuck............... 421
If your vehicle has to be stopped in an
emergency ............................................... 380
If your vehicle needs to be towed .....383
If your vehicle overheats ......................... 418
Energy monitor ............................................... 99
Engine .............................................................. 425 Accessory mode ......................................... 177
Compartment .............................................348
Engine switch................................................. 174
Hood................................................................ 346
How to start the hybrid system ............ 174
Identification number ............................... 425
If your vehicle has to be stopped in an
emergency ............................................... 380
Ignition switch (power switch) .............. 174
Overheating.................................................. 418
Power switch ................................................. 174
Engine compartment cover .................... 349
Engine coolant Capacity ......................................................... 427
Checking .........................................................351
Preparing and checking before winter .......................................................................... 279
Warning light .............................................. 389
Engine coolant temperature gauge ....... 84
Engine oil Capacity ......................................................... 426
Checking .......................................................349
Warning light .............................................. 389
Engine switch .................................................. 174
EPS (Electronic Power Steering) Function .......................................................... 272
Warning light .............................................. 390
EV drive mode................................................178
EV indicator ...................................................... 68
Event data recorder (E DR) ........................... 8
F
Flat tire ............................................................. 402
Tire pressure warning system ............ 359
Floor mats .......................................................... 24
Fluid Brake ................................................................ 429
Transmission.................................................428
Washer ...........................................................353
Fog lights Replacing light bulbs ................................375
Switch................................................................ 196
Front passenger occupant classification system ................................................................ 41
Front passenger’s seat belt reminder light .......................................................................... 393
Front seat heaters........................................300
Front seats ........................................................132 Adjustment ......................................................132
Cleaning .........................................................335
Correct driving posture ............................ 25
Driving position memory ........................ 138
Head restraints............................................... 141
Power easy access system .................... 138
Seat heaters ................................................. 300
Seat position memory .............................. 138
Front side marker lights Light switch .................................................... 190