2018 LEXUS NX300h engine coolant

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

3957-2. Steps to take in an emergency
LEXUS NX300h Owners Manu-
al_USA_OM78212U 7
When trouble arises coolant is unavailable.
6 Start the hybrid system and turn the
air conditioning system on to check
that the radiator cooling fans oper-
ate 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 oper-
ating by checking the fan sound and air
flow. If it is difficult to check these, turn the
air conditioning system on and off repeat-
edly.
(The fans may not oper ate in freezing tem-
peratures.)
7 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.
8 Check if “Engine Coolant Temp
High” 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:
Have the vehicle inspected at the
nearest Lexus dealer. 
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 (radiato r) 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. 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-
al_USA_OM78212U 8
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.

414 8-1. Specifications
LEXUS NX300h Owners Manu-
al_USA_OM78212U Glossary of tire terminology Tire related
term Meaning
Cold tire
inflation
pressure Tire pressure when the vehi-
cle has been parked for
three hours or more, or has
not been driven more than 1
mile or 1.5 km under that
condition
Maximum
inflation
pressure The maximum cold inflated
pressure to which a tire may
be inflated, shown on the
sidewall of the tire
Recom-
mended
inflation
pressure Cold tire inflation pressure
recommended by a manu-
facturer
Accessory
weight The combined weight (in
excess of those standard
items which may be
replaced) of transmission,
power steering, power
brakes, power windows,
power seats, radio and
heater, to the extent that
these items are available as
factory-installed equipment
(whether installed or not)
Curb weight The weight of a motor vehi-
cle with standard equip-
ment, including the
maximum capacity of fuel,
oil and coolant, and if so
equipped, air conditioning
and additional weight
optional engine Maximum
loaded vehi-
cle weight The sum of:
(a) Curb weight
(b) Accessory weight
(c) Vehicle capacity weight
(d) Production options
weight
Normal
occupant
weight 150 lb. (68 kg) times the
number of occupants speci-
fied in the second column of
Table 1 *
that follows
Occupant
distribution Distribution of occupants in
a vehicle as specified in the
third column of Table 1 *

below
Production
options
weight The combined weight of
installed regular production
options weighing over 5 lb.
(2.3 kg) in excess of the
standard items which they
replace, not previously con-
sidered in curb weight or
accessory weight, including
heavy duty brakes, ride lev-
elers, roof rack, heavy duty
12-volt battery, and special
trim
Rim A metal support for a tire or
a tire and tube assembly
upon which the tire beads
are seated
Rim diame-
ter
(Wheel
diameter) Nominal diameter of the
bead seat
Rim size des-
ignation Rim diameter and widthTire related
term Meaning

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