2021 LEXUS RX450h engine

3736-3. Do-it-yourself maintenance
6
Maintenance and care
●When the engine is new, for example
directly after purchasing the vehicle or
after replacing the engine
●If low quality oil or oil of an inappropriate
viscosity is used
●When driving at high engine speeds or
with a heavy load, when towing, or when
driving while accelera ting or decelerat-
ing frequently
●When leaving the engine idling for a long
time, or when driving frequently through
heavy traffic
■After changing the engine oil
The engine oil maintena nce data should be
reset. Perform the following procedures:
1 Press or of the meter control
switch to select on the multi-infor-
mation display.
2 Press or of the meter control
switch, select the “Vehicle Settings”
then “Oil Maintenance”. (To confirm
setting, press .)
3 Select the “Yes” and press .
4 A message is displayed on the
multi-information display.
■Engine coolant reservoir
The coolant level is satisfactory if it is
between the “FULL” and “LOW” lines
on the reservoir when the hybrid sys-
tem is cold.
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
( P.454)
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, service 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 re fill the vehicle.
●Be sure the engine o il filler cap is prop-
erly tightened.
Checking the coolant
A
B
C

3746-3. Do-it-yourself maintenance
■Power control unit coolant reser-
voir
The coolant level is satisfactory if it is
between the “FULL” and “LOW” lines
on the reservoir when the hybrid sys-
tem is cold.
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line.
( P.454)
■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 and radiator
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 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

3756-3. Do-it-yourself maintenance
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
brake fluid
Item
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 any washer does not work or the
warning message appears on the
multi-information display, the washer
tank may be empty. Add washer fluid.
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.
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.
Washer fluid
WARNING
■When adding washer fluid
Do not add washer fluid when the hybrid
system is hot or operating as washer fluid
contains alcohol and may catch fire if
spilled on the engine, etc.

3766-3. Do-it-yourself maintenance
RX450h
The 12-volt battery is located in the
left-hand side of luggage compart-
ment.
RX450hL
The 12-volt battery is located in the
left-hand side of luggage compart-
ment.
RX450h
1 Lift the deck board and attach the
hook. ( P.331)
NOTICE
■Do not use any fluid other than
washer fluid
Do not use soapy water or engine anti-
freeze instead of washer fluid.
Doing so may cause streaking on the
vehicle’s painted surfaces, as well as
damaging the pump leading to problems
of the washer fluid not spraying.
■Diluting washer fluid
Dilute washer fluid with water as neces-
sary.
Refer to the freezing temperatures listed
on the label of the washer fluid bottle.
12-volt battery
Location
Removing the 12-volt battery
cover

3956-3. Do-it-yourself maintenance
6
Maintenance and care
1Turn the power switch off.
2 Open the fuse box cover.
Engine compartment
Push the tab in and lift the lid off.
Driver’s side instrument panel
Remove the lid.
Luggage compartment (type A fuse
box)
RX450h:
Remove the 12-volt battery cover.
( P.376) RX450hL:
Remove the deck board and side auxiliary
box cover and 12-volt battery cover.
(
 P.376)
Luggage compartment (type B fuse
box)
RX450h:
Remove the terminal cover.
RX450hL:
Remove the terminal cover.
Checking and replacing
fuses
If any of the electrical components
do not operate, a fuse may have
blown. If this happens, check and
replace the fuses as necessary.
Checking and replacing fuses

4026-3. Do-it-yourself maintenance
6Reinstall the fender liner and install
the 3 fender liner clips.
■Front turn signal lights (vehicles
with single-bea m headlights)
1 Removing the engine compartment
cover. 1
Push the center of the clip.
2 Remove the clip.
2 For the right side only: Remove the
bolt of washer fluid inlet.
3 For the right side only: Open the
cap, remove the bracket , and
move the washer fluid inlet.
A

4046-3. Do-it-yourself maintenance
9Install the engine compartment
cover.
1 Push up center portion
2 Insert
3 Press
■Rear turn signal lights (bulb type)
1 Open the back door and apply pro-
tective tape to the vehicle body
around the taillight.
Use masking tape, etc. Do not use duct
tape, as it may leave residue or damage the
paint when removed.
2Using a flathead screwdriver,
remove the cover.
To prevent scratching the vehicle, wrap the
tip of the flathead scre wdriver with a cloth,
etc.
3 Remove the 2 screws.
4 Remove the taillight unit.
1 Attach 2 long pieces of masking

4177-2. Steps to take in an emergency
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 hybrid system
 Engine missing, stumbling or run-
ning 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