2020 LEXUS RX450H radiator cap

5947-3. Do-it-yourself maintenance
RX350/RX350L_U
Engine compartment
Washer fluid tank ( P. 603)
Engine oil filler cap ( P. 596)
Engine oil level dipstick (P. 595)
Engine coolant reservoir (P. 598) Battery
( P. 601)
Brake fluid reservoir ( P. 600)
Fuse box ( P. 625)
Radiator ( P. 599)
Condenser ( P. 599)
Electric cooling fans1
2
3
4
5
6
7
8
9
10

5987-3. Do-it-yourself maintenance
RX350/RX350L_U
The coolant level is satisfactory if it is between the “FULL” and “LOW” lines on
the reservoir when the engine 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. 692)
■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 Cool ant” is a mixture 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 radiator, hoses, engine coolant reservoir cap, 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.
Coolant
1
2
3
WARNING
■When the engine is hot
Do not remove the engine coolan t reservoir cap and radiator cap.
The cooling system may be under pressure and may spray hot coolant if the cap is
removed, causing serious injuries, such as burns.

6928-2. Steps to take in an emergency
RX350/RX350L_U
Stop the vehicle in a safe place and turn 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, insp ect the hoses and
radiator core (radiator) for any
leaks.
Radiator
Cooling fans
If a large amount of coolant leaks,
immediately contact your Lexus
dealer.
The coolant level is satisfactory if it is
between the “FULL” and “LOW”
lines on the reservoir.Reservoir
“FULL” line
“LOW” line
Radiator cap
If your vehicle overheats
The following may indicate that your vehicle is overheating.
●The needle of the engine coolant temperature gauge ( P. 86) enters the
red zone, or a loss of engine power is experienced. (For example, the vehi-
cle 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
1
2
3
1
2
4
1
2
3
4

6948-2. Steps to take in an emergency
RX350/RX350L_U
WARNING
■To prevent an accident or injury 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 h ood, 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.
●Do not loosen the radiator cap and the c oolant reservoir cap while the engine and
radiator are hot.
High temperature steam or coolant could spray out.
NOTICE
■When adding engine coolant
Add coolant slowly after the engine has cool ed 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 foreig n matter (such as sand or dust etc.).
●Do not use any coolant additive.

769Alphabetical index
RX350/RX350L_U
Radar cruise control (dynamic radar cruise control
with full-speed range) .....................300
Radiator .................................................... 599
Radio.......................................................... 420
Rear automatic air conditioning system ..................................................... 518
Rear Cross Traffic Alert ......................313
Rear Cross Traffic Auto Brake.......350
Rear door sunshades .......................... 554
Rear passengers' seat belt reminder light ..................................... 656
Rear seat Folding down the rear seatbacks ............................................. 157
Rear side marker lights Light switch ........................................... 252
Replacing light bulbs ....................... 630
Rear turn signal lights Replacing light bulbs ....................... 630
Turn signal lever .................................246
Wattage ................................................. 705
Rear view mirror Inside rear view mirror ..................... 182
Outside rear view mirrors .............. 184 Rear window defogger ........................ 513
Rear window wiper .............................. 267
Refueling...................................................269
Capacity.................................................700
Fuel types...............................................700
Opening the fuel tank cap ............ 269
When the fuel filler door cannot be opened ..........................272
Remote Touch
*.....................................496
Replacing Electronic key battery ..................... 623
Fuses ........................................................ 625
Light bulbs.............................................630
Tires ..........................................................666
Windshield wiper inserts ................. 621
Reporting safety defects for U.S. owners ......................................... 738
Resetting the message indicating maintenance is required ................ 585
Rev indicator ............................................. 88
Rev peak ..................................................... 88
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