2018 LEXUS NX300h radiator

320 6-2. Maintenance
LEXUS NX300h Owners Manu-
al_USA_OM78212U 2 Press or of the meter control
switches, sele ct the “Vehicle Settings”
and then press .
3 Press or of the meter control
switches, select the “Scheduled Mainte-
nance” and then press and hold the .
4 Select the “Yes” and push .
“The Data Has Been Reset” is displayed
on the multi-information display.
You can perform some maintenance
procedures by yourself.
Please be aware that do-it-yourself
maintenance may affect warranty cov-
erage. The use of Lexus repair manuals is recom-
mended.
For details about warra nty coverage, refer
to the separate “Owner’s Guide”, “War-
ranty and Service Guide”, “Owner’s Man-
ual Supplement” or “Warranty Booklet”.Do-it-yourself maintenance General maintenance Listed below are the general main-
tenance items that should be per-
formed at the intervals specified in
the “Warranty and Service Guide”
or “Owner’s Manual Supplement”.
It is recommended that any prob-
lem you notice should be brought to
the attention of your Lexus dealer
or qualified service shop for advice. WARNING■
If the hybrid system is operating
Turn the hybrid system off and ensure
that there is adequate ventilation before
performing maintenance checks.
Engine compartment Items Check points
Brake fluid Is the brake fluid at the cor-
rect level? ( → P.332)
Engine/power
control unit
coolant Is the engine coolant at the
correct level? ( → P.330)
Engine oil Is the engine oil at the cor-
rect level? ( → P.328)
Exhaust sys-
tem There should not be any
fumes or strange sounds.
Radiator/con-
denser The radiator and con-
denser should be free from
foreign objects. ( → P.331)
Washer fluid Is there sufficient washer
fluid? ( → P.332)

324 6-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manu-
al_USA_OM78212U 6-3.Do-it-yourself maintenance
Do-it-yourself service pre-
cautions If you perform maintenance by
yourself, be sure to follow the cor-
rect procedure as given in these
sections.
Maintenance Items Parts and tools
12-volt Bat-
tery condition
( → P.333) •Grease
•Conventional wrench
(for terminal clamp
bolts)
Brake fluid
level
( → P.332) • FMVSS No.116 DOT 3
or SAE J1703 brake
fluid
• Rag or paper towel
• Funnel (used only for
adding brake fluid)
Engine/power
control unit
coolant level
( → P.330) • “Toyota Super Long Life
Coolant” or a similar
high quality ethylene gly-
col-based non-silicate,
non-amine, non-nitrite
and non-borate coolant
with long-life hybrid
organic acid technology
For the U.S.A.:
“Toyota Super Long Life
Coolant” is pre-mixed
with 50% coolant and
50% deionized water.
For Canada:
“Toyota Super Long Life
Coolant” is pre-mixed
with 55% coolant and
45% deionized water.
• Funnel (used only for
adding coolant) Engine oil
level
( → P.328) •“Toyota Genuine Motor
Oil” or equivalent
• Rag or paper towel
• Funnel (used only for
adding engine oil)
Fuses
( → P.349) • Fuse with same amper-
age rating as original
Light bulbs
( → P.353) •Bulb with same number
and wattage rating as
original
Headlight aim • Phillips-head screw-
driver
Radiator and
condenser
( → P.331) —
Tire inflation
pressure
( → P.343) • Tire pressure gauge
• Compressed air source
Washer fluid
( → P.332) • Water or washer fluid
containing antifreeze
(for winter use)
• Funnel (used only for
adding water or washer
fluid)
WARNING
The engine compartment contains many
mechanisms and fluids that may move
suddenly, become hot, or become elec-
trically energized. To avoid death or seri-
ous injury, observe the following
precautions.
■
When working on the engine com-
partment
●
Make sure that the indicator on the
power switch and the “READY” indi-
cator are both off.
●
Keep hands, clothing and tools away
from the moving fan and engine drive
belt. Items Parts and tools

3256-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manu-
al_USA_OM78212U 6
Maintenance and care 1 Pull the hood lock release lever. The hood will pop up slightly.
2 Pull up the auxiliary catch lever and
lift the hood.WARNING●
Be careful not to touch the engine,
power control unit, radiator, exhaust
manifold, etc. right after driving as they
may be hot. Oil and other fluids may
also be hot.●
Do not leave anything that may burn
easily, such as paper and rags, in the
engine compartment.●
Do not smoke, cause sparks or expose
an open flame to fuel. Fuel fumes are
flammable.■
When working near the electric cool-
ing fans or radiator grille
Be sure the power switch is off.
With 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.
( → P.331)■
Safety glasses
Wear safety glasses to prevent flying or
falling material, fluid spray, etc. from get-
ting in your eyes.
NOTICE■
If you remove the air cleaner filter
Driving with the air cleaner filter
removed may cause excessive engine
wear due to dirt in the air. Hood
Opening the hood
WARNING
■
Pre-driving check
Check that the hood is fully closed and
locked.
If the hood is not locked properly, it may
open while the vehicle is in motion and
cause an accident, which may result in
death or serious injury.

3276-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manu-
al_USA_OM78212U 6
Maintenance and care
Fuse box ( → P.349)
Engine coolant reservoir ( → P.330)
Engine oil filler cap ( → P.329)
Power control unit coolant reservoir ( → P.331)
Brake fluid reservoir ( → P.332)
Radiator ( → P.331)
Condenser ( → P.331)
Electric cooling fans
Engine oil level dipstick ( → P.328)
Washer fluid tank ( → P.332)■
12-volt battery
→ P.333Engine compartment
Components
A
B
C
D
E
F
G
H
I
J

3316-3. Do-it-yourself maintenance
LEXUS NX300h Owners Manu-
al_USA_OM78212U 6
Maintenance and care ■
Power control unit coolant reser-
voir
Reservoir cap
“FULL” line
“LOW” lineIf the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
■
Coolant selection
Only use “Toyota Super Long Life Coolant”
or a similar high quality ethylene glycol
based non-silicate, non-amine, non-nitrite,
and non-borate coolant with long-life
hybrid organic acid technology.
U.S.A.:
“Toyota Super Long Life Coolant” is a mix-
ture of 50% coolant and 50% deionized
water.
(Minimum temperature: -31°F [-35°C])
Canada:
“Toyota Super Long Life Coolant” is a mix-
ture of 55% coolant and 45% deionized
water.
(Minimum temperature: -44°F [-42°C])
For more details about coolant, contact
your Lexus dealer.
■
If the coolant level drops within a short
time of replenishing
Visually check the radiator, hoses, engine/
power control unit coolant reservoir caps,
drain cock and water pump.
If you cannot find a leak, have your Lexus
dealer test the cap and check for leaks in
the cooling system. Check the radiator and condenser and
clear away any foreign objects.
If either of the above parts is extremely
dirty or you are not sure of their condi-
tion, have your vehicle inspected by
your Lexus dealer.A
B
C WARNING■
When the hybrid system is hot
Do not remove the en gine/power control
unit coolant reservoir caps.
The cooling system may be under pres-
sure and may spray hot coolant if the cap
is removed, causing serious injuries, such
as burns.
NOTICE■
When adding coolant
Coolant is neithe r plain water nor
straight antifreeze. The correct mixture
of water and antifreeze must be used to
provide proper lubrication, corrosion
protection and cooling. Be sure to read
the antifreeze or coolant label. ■
If you spill coolant
Be sure to wash it off with water to pre-
vent it from damaging parts or paint.
Checking the radiator and con-
denser
WARNING
■
When the hybrid system is hot
Do not touch the radiator or condenser
as they may be hot and cause serious
injuries, such as burns.

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

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