2021 TOYOTA HIGHLANDER HYBRID coolant reservoir

4166-3. Do-it-yourself maintenance
HIGHLANDER HV_U
Engine coolant reservoir ( P.418)
Fuse boxes ( P.446)
Engine oil filler cap ( P.417)
Engine oil level dipstick ( P.417)
Brake fluid reservoir ( P.420)
Washer fluid tank ( P.420)
Electric cooling fan
Condenser ( P.419)
Radiator ( P.419)
Power control unit coolant reservoir ( P.419)
■12-volt battery
 P. 4 2 1
With the engine at operating
temperature and turned off,
check the oil level on the dip-
Engine compar tment
Components
Checking and adding the
engine oil

4186-3. Do-it-yourself maintenance
HIGHLANDER HV_Ube consumed while driving. In the
following situatio
ns, oil consump-
tion may increase, and engine oil
may need to be ref illed in between
oil maintenance intervals.
●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 inap-
propriate viscosity is used
●When driving at high engine
speeds or with a heavy load,
when towing, or when driving
while accelerating o r decelerating
frequently
●When leaving the engine idling for
a long time, or wh en driving fre-
quently through heavy traffic
■Engine coolant reservoir
The coolant level is satisfactory
if it is between the “FULL” and
“LOW” lines on the reservoir
when the engine is cold.
WARNING
■Used engine oil
●Used engine oil contains poten-
tially harmful contaminants
which may cause skin disorders
such as inflammation and skin
cancer, so care should be taken
to avoid prolonged and
repeated contact. To remove
used engine oil from your skin,
wash thoroughly with soap and
water.
●Dispose of used oil and filters
only in a safe an d acceptable
manner. Do not dispose of used
oil and filters in household trash,
in sewers or onto the ground.
Call your Toyota dealer, service
station or auto parts store for
information concerning recy-
cling or disposal.
●Do not leave used engine oil
within the rea ch of children.
NOTICE
■To prevent serious engine
damage
Check the oil le vel 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 dip-
stick every time you refill the
vehicle.
●Be sure the engine oil filler cap
is properly tightened.
■If oil is spilled on the engine
cover
To prevent the engine cover from
being damaged, remove any
engine oil from the engine cover
as soon as possible using a neu-
tral detergent. Do not use an
organic solvent such as brake
cleaner.
Checking the coolant

4196-3. Do-it-yourself maintenance
6
Maintenance and care
HIGHLANDER HV_U
Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW”
line, add coolant up to the “FULL”
line. (P.504)
■Power control unit coolant
reservoir
The coolant level is satisfactory
if it is between the “FULL” and
“LOW” lines on the reservoir
when the hybrid system 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.504)
■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 mixture of 50% coolant and 50%
deionized water. (Minimum tem-
perature: -31°F [-35°C])
Canada: “Toyota Super Long Life Coolant” is
a mixture of 55% c
oolant and 45%
deionized water. (Minimum tem-
perature: -44°F [-42°C])
For more details about coolant, con-
tact your Toyota 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
Toyota dealer test the cap and
check for leaks in the cooling sys-
tem.
Check the radiator and con-
WARNING
■When the hybrid system is
hot
Do not remove the engine/power
control unit coolant reservoir caps
and radiator cap.
The cooling system may be under
pressure and may spray hot cool-
ant 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
prevent it from damaging parts or
paint.
Checking the radiator and
condenser

5047-2. Steps to take in an emergency
HIGHLANDER HV_U
If the engine coolant tempera-
ture gauge enters the red
zone or “Engine Coolant
Temp High Stop in a Safe
Place See Owner’s Manual”
is shown on the multi-informa-
tion display
1 Stop the vehicle in a safe
place and turn off the air con-
ditioning 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 radia-
tor core (radiator) for any
leaks.
Radiator
Cooling fan
If a large amount of coolant leaks,
immediately contact your Toyota
dealer.
4The coolant level is satisfac-
tory if it is between the
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL” line
“LOW” line
If your vehicle over-
heats
The following may indicate
that your vehicle is over-
heating.
The needle of the engine
coolant temperature gauge
( P.89) enters the red zone
or a loss of hybrid system
power is experienced. (For
example, the vehicle speed
does not increase.)
 “Engine Coolant Temp High
Stop in a Safe Place See
Owner’s Manual” or “Hybrid
System Overheated Output
Power Reduced” is shown
on the multi-information dis-
play.
 Steam comes out from
under the hood.
Correction procedures

5067-2. Steps to take in an emergency
HIGHLANDER HV_U
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL” line
“LOW” line
5 Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
6After stopping the hybrid sys-
tem and waiting for 5 minutes
or more, start the hybrid sys-
tem again and check if
“Hybrid System Overheated
Output Power Reduced” is
shown on the for the
multi-information display.
If the message does not disappear:
Stop the hybrid system and contact
your Toyota dealer.
If the message is not displayed:
The hybrid system temperature has
dropped and the vehicle may be
driven normally. However, if the m
essage appears
again frequently, contact your Toy-
ota dealer.
WARNING
■When inspecting under the
hood of your vehicle
Observe the following precau-
tions.
Failure to do so may result in seri-
ous injury such as burns.
●If steam is seen coming from
under the hood, do not open the
hood until the steam has sub-
sided. The engine compart-
ment may be very hot.
●After the hybrid system has
been turned off , check that the
“READY” indicator is off.
When the hybrid system is oper-
ating, the gasoline engine may
automatically start, or the cool-
ing 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
clothing (especially a tie, a scarf
or a muffler) getting caught,
resulting in serious injury.
●Do not loosen the radiator cap
and the coolant reservoir caps
while the hybrid system and
radiator are hot.
High temperature steam or
coolant could spray out.
NOTICE
■When adding engine/power
control unit coolant
Add coolant slowly after the
hybrid system has cooled down
sufficiently. Adding cool coolant to
a hot hybrid system too quickly
can cause damage to the hybrid
system.