engine coolant LEXUS RCF 2018 User Guide

3976-3. Do-it-yourself maintenance
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U) 6
Maintenance and care 
RC350/RC300 AWD
Engine compartment
Fuse boxes (  P. 429)
Battery (  P. 408)
Engine oil level dipstick
(  P. 400)
Engine coolant reservoir
(  P. 404)
Engine oil filler cap (  P. 402) Brake fluid reservoir (  P. 407)
Washer fluid tank (  P. 411)
Electric cooling fans
Condenser (  P. 406)
Radiator (  P. 406)1
2
3
4
5 6
7
8
9
10

398 6-3. Do-it-yourself maintenance
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)
RC300
Fuse boxes (  P. 429)
Battery (  P. 408)
Engine oil level dipstick
(  P. 400)
Engine oil filler cap (  P. 402)
Engine coolant reservoir
(  P. 404)
Brake fluid reservoir (  P. 407) Washer fluid tank (  P. 411)
Electric cooling fans
Condenser (  P. 406)
Intercooler radiator (  P. 406)
Radiator (  P. 406)
Intercooler coolant reservoir
(  P. 404)1
2
3
4
5
6 7
8
9
10
11
12

3996-3. Do-it-yourself maintenance
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U) 6
Maintenance and care 
RC F
Fuse boxes (  P. 429)
Battery (  P. 408)
Engine oil level dipstick
(  P. 400)
Engine coolant reservoir
(  P. 404)
Engine oil filler cap (  P. 402) Brake fluid reservoir (  P. 407)
Washer fluid tank (  P. 411)
Electric cooling fans
Condenser (  P. 406)
Radiator (  P. 406)1
2
3
4
5 6
7
8
9
10

404 6-3. Do-it-yourself maintenance
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)■
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.
Coolant 
RC350/RC300 AWD 
RC300
RC F
Reservoir cap
“FULL” line
“LOW” line If the level is on or below the “LOW” lin e, add coolant up to the “FULL” line.
(  P. 526) 1
2
3

4056-3. Do-it-yourself maintenance
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U) 6
Maintenance and care ■
Intercooler coolant reservoir (RC300)
The coolant level is satisfactory if it is between the “F” and “L” lines on the res-
ervoir 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. 526)■
Coolant selection
Only use “Toyota Super Long Life Coolant” or a similar high qu ality 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 Cool ant” is a mixture 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, ho ses, engine and intercooler coolant reservoir caps, drain
cock and water pump.
If you cannot find a leak, have your Lexus de aler test the cap and check for leaks in the
cooling system. 1
2
3

406 6-3. Do-it-yourself maintenance
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)Check the radiator, condenser and interc ooler radiator and clear away any for-
eign objects.
If any of the above parts are extremely dirt y or you are not sure of their condition,
have your vehicle inspecte d by your Lexus dealer.WARNING ■
When the engine is hot (RC350/RC300)
Do not remove the engine coolant reservoir cap, intercooler coolant reservoir cap and
coolant inlet cap. (  P. 530)
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. 530)
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, condenser and intercooler radiator (if equipped)
WARNING ■
When the engine is hot
Do not touch the radiator, condenser or inte rcooler as they may be hot and cause seri-
ous injuries, such as burns.

4517-2. Steps to take in an emergency
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U) 7
When trouble arises ●
Fluid leaks under the vehicle.
(Water dripping from the air co nditioning 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 f eeling, pedal almost touches the floorIf 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

4677-2. Steps to take in an emergency
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U) 7
When trouble arises Indicates a malfunction in:
• The SRS airbag system;
• The front passenger occupant classification system; or
• The seat belt pretensioner system
A buzzer also sounds.
 Have the vehicle inspected by your Lexus dealer.
Indicates a malfunction in:
• The ABS; or
• The brake assist system
A buzzer also sounds.
 Have the vehicle inspected by your Lexus dealer.
Indicates that the engine coolant temperature is too high
A buzzer also sounds.
 P. 526Warning message Details/Actions(U.S.A.) (Canada)

526 7-2. Steps to take in an emergency
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U)●
The engine coolant temperature gauge (  P. 91, 96) is in the red zone or a
loss of engine power is experienced. (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.
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.If your vehicle overheats The following may indicate that your vehicle is overheating.
Correction procedures 1
2

5277-2. Steps to take in an emergency
RC350_RC300 AWD_RC3 00_RC F_U(OM24748U) 7
When trouble arises After the engine has cooled down suff iciently, inspect th e hoses and radiator
core (radiator) for any leaks.
Radiator
Cooling fans If a large amount of coolant leaks, immediately contact your Lexus dealer. 3
1
2
RC350/RC300 AWD 
RC300
RC F