2015 LEXUS RC350 coolant temperature

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

5318-2. Steps to take in an emergency
8
When trouble arises
RC350/RCF_U (OM24636U)
●Fluid leaks under the vehicle.
(Water dripping from the air conditioning after use is normal.)
●Flat-looking tires or uneven tire wear
●Engine coolant temperature gauge cont inually points higher than normal.
●Changes in exhaust sound
●Excessive tire squeal when cornering
●Strange noises related to the suspension system
●Pinging or other noises related to the engine
●Engine missing, 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. Contact your Lexus dealer as soon as possible.
Visible symptoms
Audible symptoms
Operational symptoms

5448-2. Steps to take in an emergency
RC350/RCF_U (OM24636U)
Indicates that the engine coolant temperature is too highA buzzer also sounds.
 P. 5 9 7
(If equipped)
Indicates that the radar sensor is dirty or covered with
ice
A buzzer also sounds.
 Clean the sensor.
(If equipped)
Indicates that the dynamic radar cruise control system is
unable to judge vehicle-to-vehicle distance
A buzzer also sounds.
 Tu r n o f f s n o w m o d e .
If the windshield wipers are on, turn them off or set
them to a mode other than AUTO or high speed
wiper operation.
(If equipped)
Indicates that the LDA (Lane Departure Alert) system is
suspended (The camera sensor temperature is higher
than the operation temperature range)
A buzzer also sounds.
 Restart the LDA after driving for a while.
Wa r n i n g m e s s a g eDetails/Actions

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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2
3
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2
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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1
2
3
RC350RC F
5
RC350RC F
6
7

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.

670Alphabetical index
RC350/RCF_U (OM24636U)
Engine ....................................................... 606ACCESSORY mode....................... 194
Compartment...................................... 479
Engine switch ........................................ 193
Hood ........................................................475
How to start the engine ................... 193
Identification number ...................... 606
If the engine will not start............... 587
Ignition switch (engine switch)..... 193
Overheating .........................................597
Engine coolant....................................... 484 Capacity .................................................. 610
Checking............................................... 484
Preparing and checking before winter ..................................... 315
Engine coolant temperature gauge ................................................90, 96
Engine immobilizer system ..................76
Engine oil .................................................. 481 Capacity ................................................ 607
Checking................................................. 481
Preparing and checking before winter ..................................... 315
Engine oil temperature gauge ........... 96
Engine switch ...........................................193
Enhanced VSC ..................................... 282
EPS (Electric Power Steering) ....... 283 Warning light .......................................534
Event data recorder (EDR) ...................10
Expert mode ........................................... 286 First-aid kit storage belt......................434
Flat tire
Vehicles with a spare tire ............. 560
Vehicles with emergency tire puncture repair kit ......................... 574
Floor mats................................................... 30
Fluid Automatic transmission ..................... 611
Brake..........................................................613
Washer ...................................................490
Fog lights.................................................... 216 Replacing light bulbs .........................519
Switch ........................................................ 216
Footwell light .......................................... 428 Wattage ...................................................619
Front fog lights......................................... 216 Replacing light bulbs .........................519
Switch ........................................................ 216
Front passenger occupant classification system ........................... 50
Front seats ................................................. 152 Adjustment.............................................. 152
Cleaning................................................. 463
Correct driving posture .....................32
Driving position memory................. 157
Head restraints ...................................... 161
Jam protection function....................153
Seat heaters .......................................... 426
Seat position memory ....................... 157
Seat ventilators.....................................427F