2020 LEXUS RC300 cooling

2506-3. Do-it-yourself maintenance
RC300Fuse boxes ( P.269)
Battery ( P.255)
Engine oil level dipstick ( P.250)
Engine oil filler cap ( P.250)
Engine coolant reservoir ( P.252)
Brake fluid reservoir ( P.254)
Washer fluid tank ( P.256)
Electric cooling fans
Condenser ( P.254)
Intercooler radiator ( P.254)
Radiator ( P.254)
Intercooler coolant reservoir ( P.252)
With the engine at operating tempera-
ture and turned off, check the oil level
on the dipstick.
■Checking the engine oil
1 Park the vehicle on level ground.
After warming up the engine and
turning it off, wait more than 5 min-
utes for the oil to drain back into the
bottom of the engine.
A
B
C
D
E
F
G
H
I
J
K
L
Checking and adding the engine
oil

2536-3. Do-it-yourself maintenance
6
Maintenance and care
on the reservoir when the engine is
cold.
■Engine coolant reservoir
RC350/RC300 AWD
RC300Reservoir cap
“FULL” line
“LOW” line
If the level is on or below the “LOW” line,
add coolant up to the “FULL” line. ( P.311)
■Intercooler coolant reservoir
(RC300)
The coolant level is satisfactory if it is
between the “F” and “L” lines on the
reservoir when the engine is cold. Reservoir cap
“F” line
“L” line
If the level is on or
below the “L” line, add
coolant up to the “F” line. ( P.311)
■Coolant selection
Only use “Toyota Super Long Life Coolant”
or a similar high qua lity 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 radi ator, hoses, engine
and intercooler 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.
A
B
C
A
B
C

2546-3. Do-it-yourself maintenance
Check the radiator, condenser and
intercooler radiator and clear away
any foreign objects.
If any of the above parts are extremely
dirty or you are not sure of their condi-
tion, have your vehicle inspected by
your Lexus dealer.
■Checking fluid level
The brake fluid level should be
between the “MAX” and “MIN” lines
on the tank.
RC350/RC300 AWD
RC300
■Adding fluid
Make sure to check the fluid type and
prepare the necessary item.
 Fluid type
SAE J1703 or FMVSS No.116 DOT 3
brake fluid
SAE J1704 or FMVSS No.116 DOT 4
brake fluid
Item
Clean funnel
WARNING
■When the engine is hot
Do not remove the engine coolant reser-
voir cap, intercooler coolant reservoir
cap and coolant inlet cap. ( P.314)
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 damagi ng parts or paint.
Checking the radiator, con-
denser and intercooler radiator
(if equipped)
WARNING
■When the engine is hot
Do not touch the radiator, condenser or
intercooler radiator as they may be hot
and cause serious injuries, such as burns.
Checking and adding the brake
fluid

3117-2. Steps to take in an emergency
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
radiator core (radiator) for any
leaks.
WARNING
●When working with the battery, always
wear safety glasses and take care not
to allow any battery fluids (acid) to
come into contact with skin, clothing
or the vehicle body.
●Do not lean over the battery.
●In the event that battery fluid comes
into contact with the skin or eyes,
immediately wash the affected area
with water and seek medical attention.
Place a wet sponge or cloth over the
affected area until medical attention
can be received.
●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 engine coolant temperature
gauge ( P.64) is in the red zone
or a loss of engine power is expe-
rienced. (For example, the vehicle
speed does not increase.)
 “Engine Coolant Temp High Stop
in a Safe Place See Owner’s
Manual” is shown on the
multi-information display.
 Steam comes out from under the
hood.
Correction procedures

3127-2. Steps to take in an emergency
RC350/RC300 AWD
Radiator
Cooling fans
If a large amount of coolant leaks, immedi-
ately contact your Lexus dealer.
 RC300
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 (“FULL” or “F”)
and low (“LOW” or “L”) lines on the
reservoir.
 Engine (RC350/RC300 AWD) Reservoir cap
“FULL” or “F”
“LOW” or “L”
 Engine (RC300)
Reservoir cap
“FULL” or “F”
“LOW” or “L”
 Intercooler (RC300)
Reservoir cap
“FULL” or “F”
“LOW” or “L”
A
B
A
B
A
B
C
A
B
C
A
B
C

3137-2. Steps to take in an emergency
7
When trouble arises
5Add coolant if necessary.
Water can be used in an emergency if
coolant is unavailable.
Engine (RC350/RC300 AWD)
 Engine (RC300)
 Intercooler (RC300)
6
Start the engine 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.)
7If the fans are not operating:
Stop the engine immediately and
contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the
nearest Lexus dealer.
WARNING
■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.
●Keep hands and clothing (especially a
tie, a scarf or a muffler) away from the
fans and belts. Failure to do so may
cause the hands or clothing to be
caught, resulting in serious injury.

3147-2. Steps to take in an emergency
WARNING
●RC350/RC300 AWD: While the
engine and radiator are hot, do not
loosen or remove the coolant reser-
voir cap or coolant inlet cap. (The
coolant inlet cap is located under the
engine cover.)
High temperature steam or coolant
could spray out.
●RC300: While the engine and radia-
tors are hot, do not loosen or remove
the coolant reservoir cap, coolant inlet
cap, or intercooler coolant reservoir
cap.
High temperature steam or coolant
could spray out.
NOTICE
■When adding engine coolant
Add coolant slowly after the engine has
cooled down sufficiently. Adding cool
coolant to a hot engine too quickly can
cause damage to the engine.
■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.

3218-1. Specifications
8
Vehicle specifications
Outside temperature
Oil viscosity (0W-20 is explained here
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 fluid capacity is a reference quantity. If replacement is necessary, contact your Lexus dealer.
A
Cooling system
Capacity*
RC350/RC3
00 AWD10.0 qt. (9.5 L, 8.4 Imp. qt.)
RC300
Gasoline engine
8.5 qt. (8.0 L, 7.0 Imp. qt.)
Intercooler
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 ethylene glycol-based non-silicate,
non-amine, non-nitrite, and non-borate coolant with
long-life hybrid orga nic acid technology
Do not use plain water alone.