2020 LEXUS NX300 engine coolant

3356-3. Do-it-yourself maintenance
LEXUS NX300 Owners Manual_USA_M78389_en
6
Maintenance and care
Fuse box (P.358)
Engine coolant reservoir ( P.338)
Engine oil filler cap ( P.336)
Engine oil level dipstick ( P.336)
Intercooler coolant reservoir ( P.338)
Battery ( P.340)
Brake fluid reservoir ( P.340)
Radiator ( P.339)
Condenser ( P.339)
Electric cooling fans
Washer fluid tank ( P.342)
Engine compartment
Components
A
B
C
D
E
F
G
H
I
J
K

3386-3. Do-it-yourself maintenance
LEXUS NX300 Owners Manual_USA_M78389_en
2
Press or of the meter control
switches, select the “Vehicle Settings”
and then press .
3
Press or of the meter control
switches, select the “Oil Maintenance”
and then press and hold the .
4
Select the “Yes” and push .
“The Data Has Been Reset” is displayed
on the multi-information display.
The coolant level is satisfactory if it is
between the “FULL” and “LOW” lines
on the reservoir when the engine is
cold.
■Engine coolant reservoir
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
(  P.403)
WARNING
■Used engine oil
●Used engine oil contains potentially
harmful contaminants which may
cause skin disorders such as inflamma-
tion and skin cancer, so care should be
taken to avoid prolonged and
repeated contact. To remove used
engine oil from your skin, wash thor-
oughly with soap and water.
●Dispose of used oil and filters only in a
safe and acceptable manner. Do not
dispose of used oil and filters in house-
hold trash, in sewers or onto the
ground. Call your Lexus dealer, ser-
vice station or auto parts store for
information concerning recycling or
disposal.
●Do not leave used engine oil within the
reach of children.
NOTICE
■To prevent serious engine damage
Check the oil level on a regular basis.
■When replacing the engine oil
●Be careful not to spill engine oil on the
vehicle components.
●Avoid overfilling, or the engine could
be damaged.
●Check the oil level on the dipstick
every time you refill the vehicle.
●Be sure the engine o il filler cap is prop-
erly tightened.
Checking the engine coolant
A
B
C

3396-3. Do-it-yourself maintenance
LEXUS NX300 Owners Manual_USA_M78389_en
6
Maintenance and care
■Intercooler coolant reservoir
Reservoir cap
“FULL” line
“LOW” line
If 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
coolant reservoir cap, 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 engine is hot
Do not remove the engine coolant reser-
voir and the intercooler coolant reservoir
cap.
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 neither 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 engine is hot
Do not touch the radiator or condenser
as they may be hot and cause serious
injuries, such as burns.

3406-3. Do-it-yourself maintenance
LEXUS NX300 Owners Manual_USA_M78389_en
■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.
Check the battery as follows.
■Battery exterior
Make sure that the battery terminals
are not corroded and that there are no
loose connections, cracks, or loose
clamps.
Terminals
Hold-down clamp
WARNING
■When the electric cooling fans are
operating
Do not touch the engine compartment.
With the engine switch in IGNITION
ON mode, the electric cooling fans may
automatically start to run if the air condi-
tioning is on and/or the coolant tempera-
ture is high. Be sure the engine switch is
off when working near the electric cool-
ing fans or radiatorgrille.
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 the battery
A
B

3737-2. Steps to take in an emergency
LEXUS NX300 Owners Manual_USA_M78389_en
7
When trouble arises
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 engine
 Engine misfire or misses, stumbling
or running roughly
 Appreciable loss of power
 Vehicle pulls heavily to one side
when braking 
Vehicle pulls heavily to one side
when driving on a level road
 Loss of brake effectiveness, spongy
feeling, pedal almost touches the
floor
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

3767-2. Steps to take in an emergency
LEXUS NX300 Owners Manual_USA_M78389_en
■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 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.403)
Warning lightDetails/Actions
(Yellow)
Indicates a malfunction in 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 electronic engine control system;
 The electronic throttle control system; or
 The electronic automatic transmission control system
 Have the vehicle inspected by your Lexus dealer
immediately.
Warning lightDetails/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.

3867-2. Steps to take in an emergency
LEXUS NX300 Owners Manual_USA_M78389_en
speed range
■If “Radar Cruise Control Unavailable
See Owner’s Manual” is shown
The dynamic radar cruise control with full-
speed range system is suspended tempo-
rarily or until the problem shown in the mes-
sage is resolved. (causes and coping
methods: P.197)
■If “Radar Cruise Control Unavailable” is
shown
The dynamic radar cruise control with full-
speed range system cannot be used tempo-
rarily. Use the system when it becomes
available again.
■If “Oil Maintenance Required Soon” is
shown
Indicates that the engine oil is scheduled to
be changed. (The indicator will not work
properly unless the oil maintenance data
has been reset.)
Check the engine oil, and change if neces-
sary. After changing the engine oil, the oil
change system shou ld be reset. (P.337)
■If “Oil Maintenance Required” is shown
Indicates that the engine oil should be
changed. (After the engine oil is changed
and the oil maintenance data has been
reset.)
Check and change the en gine oil, and oil fil-
ter by your Lexus deal er. After changing the
engine oil, the oil change system should be
reset. ( P.337)
■If “See Owner’s Manual” is shown
●If the following messages are shown, fol-
lowing the instructions, accordingly.
• “Engine Coolant Temp High” ( P.403)
●If the following messages are shown,
there may be a malfunction.
Immediately have the vehicle inspected
by your Lexus dealer.
• “Braking Power Low”
• “Smart Access System Malfunction”
●If the following messages are shown,
there may be a malfunction.
Immediately stop the vehicle in a safe
place and contact your Lexus dealer.
Continuing to drive the vehicle may be
dangerous.
• “Oil Pressure Low” • “Charging System Malfunction”
• “Transmission Fluid Temp High”
■Warning buzzer
 P.382
NOTICE
■“High Power Consumption Partial
Limit On AC/Heater Operation” is
frequently shown
There is a possible malfunction relating
to the charging system or the battery
may be deteriorating. Have the vehicle
inspected by your Lexus dealer.

4037-2. Steps to take in an emergency
LEXUS NX300 Owners Manual_USA_M78389_en
7
When trouble arises
1Stop the vehicle in a safe place and
turn off the air conditioning system,
and then stop the engine.
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 engine has cooled down
sufficiently, inspect the hoses and
WARNING
●Always wash your hands after handling
the battery support, terminals, and
other battery-related parts.
●Do not allow children near the battery.
NOTICE
■When handling jumper cables
When connecting the jumper cables,
ensure that they do not become entan-
gled in the cooling fans or engine drive
belt.
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
engine power is experienced.
(For example, the vehicle speed
does not increase.)
 “Engine Coolant Temp High” is
shown on the multi-information
display.
 Steam comes out from under the
hood.
Correction procedures