2018 LEXUS NX300h coolant temperature

332 6-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manu-
al_USA_OM78212U ■
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 need s frequent refilling,
there may be a serious problem.
Checking and adding the washer
fluid

3637-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 7
When trouble arises 3 Insert the towing eyelet into the
hole and tighten partially by hand.
4 Tighten down the towing eyelet
securely using a wheel nut wrench.
5 Securely attach cables or chains to
the towing eyelet.Take care not to damage the vehicle body.
6 Enter the vehicle being towed and
start the hybrid system.If the hybrid system does not start, turn the
power switch to ON mode.
7 Shift the shift lever to N and release
the parking brake.When the shift lever cannot be shifted:
→ P.174
■
While towing
If the hybrid system is off, the power assist
for the brakes and steering will not function,
marking steering and braking more difficult.
■
Wheel nut wrench
Wheel nut wrench is installed in luggage
compartment. ( → P.378)  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 brakingIf 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

366 7-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U ■
High coolant temperature warning light (warning buzzer) *
*
: This light illuminates on the multi-information display. ■
Brake system warning light
■
Malfunction indicator lamp
■
SRS warning light Warning light Details/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.394)
Warning light Details/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 light Details/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.
Warning light Details/Actions
Indicates a malfunction in:
 The SRS airbag system;
 The front passenger occupant classification system; or
 The seat belt pretensioner system
→ Have the vehicle inspected by your Lexus dealer
immediately.

394 7-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 
“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 and radiator core (radiator) for any
leaks.
Radiator
Cooling fans If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
4 The 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 If your vehicle overheats The following may indicate that
your vehicle is overheating.
 The needle of the engine coolant
temperature gauge ( → P.79)
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 A
B
A
B
C

396 7-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U Water can be used in an emergency if
coolant is unavailable.
6 After 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.
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. ●
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 dama ge 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.

4038-1. Specifications
LEXUS NX300h Owners Manu-
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Vehicle specifications 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.
*
: The coolant capacity is the quantity of reference.
If replacement is necessary, contact your Lexus dealer.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 unit 3.3 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.

450 Alphabetical Index
LEXUS NX300h Owners Manu-
al_USA_OM78212U Accessory mode .........................................170
Compartment ............................................. 327
Engine switch................................................ 168
Hood................................................................ 325
How to start the hybrid system ........... 168
Identification number ................................ 401
If your vehicle has to be stopped in an
emergency ............................................... 358
Ignition switch (power switch) ............. 168
Overheating................................................. 394
Power switch ................................................ 168
Engine compartment cover .................... 328
Engine coolant
Capacity .........................................................403
Checking .......................................................330
Preparing and checking before winter
......................................................................... 257
Warning light ...............................................366
Engine coolant temperature gauge ........79
Engine oil
Capacity ......................................................... 402
Checking ....................................................... 328
Warning light ...............................................366
Engine oil maintenance data .................. 329
Engine switch ................................................. 168
EPS (Electronic Power Steering)
Function ..........................................................250
Warning light ............................................... 367
EV drive mode................................................. 171
EV indicator ...................................................... 62
Event data recorder (EDR) ............................7 F
Flat tire ..............................................................377
Tire pressure warning system ............ 338
Floor mats .......................................................... 24
Fluid
Brake ............................................................... 405
Transmission................................................ 404
Washer ........................................................... 332
Fog lights
Replacing light bulbs ................................353
Switch................................................................ 189
Front passenger occupant classification
system ................................................................ 41
Front passenger’s seat belt reminder light
.......................................................................... 369
Front seats ........................................................128
Adjustment ..................................................... 128
Cleaning ...........................................................317
Correct driving posture ............................ 25
Driving position memory .........................134
Head restraints..............................................137
Power easy access system .....................134
Seat heaters .................................................. 276
Seat position memory ...............................134
Front side marker lights
Light switch .................................................... 183
Replacing light bulbs ................................354
Wattage ..........................................................407
Front turn signal lights
Replacing light bulbs ................... 353, 354
Turn signal lever ...........................................176
Wattage ..........................................................407
Fuel
Capacity .......................................................... 401
Fuel gauge ........................................................ 79
Gas station information ......................... 460
Information ................................................... 408
Refueling.......................................................... 196
Type ................................................................... 401
Warning light .............................................. 369
Fuel filler door .................................................196

457What to do if... (Troubleshooting)
LEXUS NX300h Owners Manu-
al_USA_OM78212U Alphabetical Index
457Replacing ........................................................377
Rotating tires ................................................ 337
Size....................................................................406
Snow tires ...................................................... 257
Spare tire............................................ 377, 406
Tire identification number .........................411
Tire pressure warning system .............338
Uniform Tire Quality Grading..............413
Warning light ............................................... 370
Tools.................................................................. 378
Top tether strap................................................57
Total load capacity ......................................400
Towing
Dinghy towing ............................................... 167
Emergency towing ...................................360
Towing eyelet .............................................. 362
Trailer sway control ..................................250
Trailer towing ...................................... 159, 167
TRAC (Traction Control) ........................ 250
Traction battery (Hybrid battery) ............ 64
Hybrid battery (traction battery) air
intake and discharge vents................... 66
Location............................................................. 64
Specification .................................................. 401
Warning messages ..................................... 67
Traction motor (electric motor) ................. 61
Trailer sway control .................................... 250
Trailer towing ........................................ 159, 167
Transmission
Hybrid transmission ................................... 173
Selecting a driving mode....................... 249
Trip meters .........................................................79
Turn signal lights
Replacing light bulbs....................353, 354
Turn signal lever ........................................... 176
Wattage.......................................................... 407
V
Vanity lights
Vanity lights ..................................................288
Wattage.......................................................... 407
Vanity mirrors ...............................................288 Vanity lights ................................................. 288
Vehicle data recordings ..................................7
Vehicle identification number ................400
Vehicle Stability Control (VSC) ........... 250
VSC (Vehicle Stability Control) ........... 250 W
Warning buzzers
Approach warning.................................... 223
Downshifting ..................................................176
Intuitive parking assist .............................. 232
Light reminder .............................................. 184
Open door ..................................................... 107
Seat belt reminder ........................ 369, 370
Vehicle sway warning ................................ 211
Warning lights
ABS ................................................................... 367
Brake hold operated indicator .......... 368
Brake Override System ...........................371
Brake system............................................... 365
Charging system....................................... 365
Drive-Start Control.....................................371
Electric power steering........................... 367
High coolant temperature.................... 366
LDA indicator ............................................. 368
Low engine oil pressure........................ 365
Low fuel level .............................................. 369
Malfunction indicator lamp .................. 366
Master warning light.................................370
Parking brake indicator ......................... 369
PCS warning light ..................................... 367
PKSB OFF indicator ............................... 368
Seat belt reminder light.............. 369, 370
Slip indicator ................................................ 368
SRS ................................................................... 366
Tire pressure ................................................370
Warning messages ..................................... 374
Washer
Checking ....................................................... 332
Low washer fluid warning message332,
374
Preparing and checking before winter