2015 LEXUS RC350 cooling

4797-3. Do-it-yourself maintenance
7
Maintenance and care
RC350/RCF_U (OM24636U)
RC350
Engine compartment
Fuse boxes (P. 5 0 9 )
Battery ( P. 4 8 7 )
Engine oil level dipstick (P. 4 8 1 )
Engine coolant reservoir (P. 4 8 4 )
Engine oil filler cap ( P. 4 8 2 )Brake fluid reservoir (
P. 4 8 6 )
Wa s h e r f l u i d t a n k ( P. 4 9 0 )
Electric cooling fans
Condenser ( P. 4 8 5 )
Radiator ( P. 4 8 5 )1
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5
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9
10

4807-3. Do-it-yourself maintenance
RC350/RCF_U (OM24636U)
RC F
Fuse boxes ( P. 5 0 9 )
Battery ( P. 4 8 7 )
Engine oil level dipstick (P. 4 8 1 )
Engine coolant reservoir (P. 4 8 4 )
Engine oil filler cap ( P. 4 8 2 )Brake fluid reservoir (
P. 4 8 6 )
Wa s h e r f l u i d t a n k ( P. 4 9 0 )
Electric cooling fans
Condenser ( P. 4 8 5 )
Radiator ( P. 4 8 5 )1
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5
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8
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10

4847-3. Do-it-yourself maintenance
RC350/RCF_U (OM24636U)
The coolant level is satisfactory if it is between the “FULL” and “LOW” lines on
the reservoir when the engine is cold.
If the level is on or below the “LOW” line, add coolant up to the “FULL” line.
(  P. 5 9 7 )
■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 mixt ure of 50% coolant and 50% deionized water.
(Minimum temperature: -31 F [-35 C])
Canada:
“Toyota Super Long Life Coolant” is a mixt ure of 55% coolant and 45% deionized water.
(Minimum temperature: -44 F [-42 C])
For more details about engine 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.
Engine coolant
RC350RC F
Reservoir cap
“FULL” line “LOW” line
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2
3

4857-3. Do-it-yourself maintenance
7
Maintenance and care
RC350/RCF_U (OM24636U)
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.
WA R N I N G
■When the engine is hot (RC350)
Do not remove the engine coolant reservoir cap or radiator cap. (P. 599)
The cooling system may be under pressure and may spray hot coolant if the cap is
removed, causing serious injuries, such as burns.
■When the engine is hot (RC F)
Do not remove the engine coolant reservoir cap. ( P. 5 9 9 )
The cooling system may be under pressure 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 cool-
ing. 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.
Radiator and condenser
WA R N I N G
■When the engine is hot
Do not touch the radiator or condenser as they may be hot and cause serious injuries,
such as burns.

5968-2. Steps to take in an emergency
RC350/RCF_U (OM24636U)
WA R N I N G
■Avoiding battery fires or explosions
Observe the following precautions to prevent accidentally igniting the flammable gas
that may be emitted from the battery:
●Make sure each jumper cable is connected to the correct terminal and that it is not
unintentionally in contact with any other than the intended terminal.
●Do not allow the other end of the jumper cable connected to the “+” terminal to come
into contact with any other parts or metal surfaces in the area, such as brackets or
unpainted metal.
●Do not allow the + and - clamps of the jump er cables to come into contact with each
other.
●Do not smoke, use matches, cigarette lighters or allow open flame near the battery.
■Battery precautions
The battery contains poisonous and corrosive acidic electrolyte, while related parts
contain lead and lead comp ounds. Observe the following precautions when handling
the battery:
●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 bat-
tery-related parts.
●Do not allow children near the battery.
NOTICE
■When handling jumper cables
When connecting the jumper cables, ensure th at they do not become entangled in the
cooling fans or engine drive belt.

5978-2. Steps to take in an emergency
8
When trouble arises
RC350/RCF_U (OM24636U)
●The engine coolant temperature gauge (P. 90, 96) is in the red zone or a
loss of engine power is experienced. (F or example, the vehicle speed does not
increase.)
●“Engine Coolant High Temperature” is shown on the multi-information dis-
play.
●Steam comes out from under the hood.
Stop the vehicle in a safe place and tu rn off the air conditioning system, and
then stop the engine.
If you see steam:
Carefully lift the hood after the steam subsides.
If you do not see steam:
Carefully lift the hood.
After the engine has cooled down sufficiently, inspect the hoses and radiator
core (radiator) for any leaks.
Radiator
Cooling fans
If a large amount of coolant leaks, immediately contact your Lexus dealer.
If your vehicle overheats
The following may indicate that your vehicle is overheating.
Correction procedures
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RC350RC F

5988-2. Steps to take in an emergency
RC350/RCF_U (OM24636U)
The coolant level is satisfactory if it is between the “FULL” and “LOW” lines on
the reservoir.Reservoir
“FULL”
“LOW”
Add coolant if necessary.
Water can be used in an emerge ncy if coolant is unavailable.
Start the engine and turn the air conditioning system on to check that the radi-
ator cooling fans operate 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 th ese, turn the air conditioning system on and off repeatedly.
(The fan may not operate in freezing temperatures.)
If 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.
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RC350RC F
5
RC350RC F
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5998-2. Steps to take in an emergency
8
When trouble arises
RC350/RCF_U (OM24636U)
WA R N I N G
■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 compartment 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 seri-
ous injury.
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 system
Observe the following precautions:
●Avoid contaminating the coolant with foreign matter (such as sand or dust etc.).
●Do not use any coolant additive.
●RC350: While the engine and radiator are
hot, do not loosen or remove the coolant res-
ervoir cap or radiator cap. (The radiator cap
is located under the engine cover.)
High temperature steam or coolant could
spray out.
●RC F: While the engine and radiator are hot,
do not loosen or remove the coolant reser-
voir cap.
High temperature steam or coolant could
spray out.