2016 LEXUS RX350 cooling

578 7-3. Do-it-yourself maintenance
RX350_U_OM48E90U 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. 668)■
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 Coolant” is a mixt ure 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 dealer test the cap and check for leaks in the
cooling system.Coolant 1
2
3
WA R N I N G ■
When the engine is hot
Do not remove the engine coolant 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.

6678-2. Steps to take in an emergency
8
When trouble arises
RX350_U_OM48E90U WA R N I N G ■
Avoiding battery fires or explosions
Observe the following precautions to preven t 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 in to 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.

668 8-2. Steps to take in an emergency
RX350_U_OM48E90U 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.
The coolant level is satisfactory if it is
between the “FULL” and “LOW”
lines on the reservoir.
Reservoir
“FULL” line
“LOW” line
Radiator capIf your vehicle overheats The following may indicate that your vehicle is overheating. ●
The needle of the engine coolant temperature gauge (  P. 8 5 ) e n t e r s t h e
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

6698-2. Steps to take in an emergency
8
When trouble arises
RX350_U_OM48E90U Add coolant if necessary. Water can be used in an emergency 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 these, turn the air conditioning system on and off repeatedly.
(The fans may not operate in freezing temperatures.)
If the fans are not operating:
Stop the engine immediately an d contact your Lexus dealer.
If the fans are operating:
Have the vehicle inspected at the nearest Lexus dealer.
Check if “Engine Coolant Temp High St op in a Safe Place See Owner’s Man-
ual” is shown on the multi-information display.
If the message does not disappear:
Stop the engine and contact your Lexus dealer.
If the message is not displayed:
Have the vehicle inspected at the nearest Lexus dealer. 5
6
7
8

670 8-2. Steps to take in an emergency
RX350_U_OM48E90U WA R N I N G ■
To prevent an accident or injury when in specting 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 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.

678 9-1. Specifications
RX350_U_OM48E90U * : The coolant capacity is a reference quantity.
If replacement is necessary, contact your Lexus dealer.Cooling system Capacity
* 
Vehicles without towing package
9.5 qt. (9.0 L, 7.9 Imp. qt.) 
Vehicles with towing package
10.5 qt. (9.9 L, 8.7 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 organic
acid technology
Do not use plain water alone.
Ignition system (spark plug) Make DENSO FK20HBR8
Gap 0.03 in. (0.8 mm)
NOTICE ■
Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust the spark plug gap.
Electrical system Battery
Open voltage at 68  F (20  C): 12.6 V or higher: Fully charged
12.2 — 12.4 V: Half charged
12.0 V or lower: Discharged
(Voltage is checked 20 minutes after the engine
and all lights ar e turned off.)
Charging rates 5 A max.

735Alphabetical index
RX350_U_OM48E90U Coolant
Capacity ................................................ 678
Checking............................................... 578
Preparing and checking
before winter ................................... 380
Cooling system ..................................... 578
Engine overheating.......................... 668
Cornering lights .................................... 242
Cruise control
Cruise control......................................326
Dynamic radar cruise control....... 314
Dynamic radar cruise control
with full-speed range ................... 302
Cup holders ..............................................514
Curtain shield airbags ........................... 37
Customizable features ....................... 699
Customized mode ............................... 369
Daytime running light system .......... 243
Defogger
Outside rear view mirrors ............ 500
Rear window .......................................500
Windshield ........................................... 500
Differential ............................................... 679
Dimension ............................................... 674
Dinghy towing..........................................219
Display
Dynamic radar cruise control....... 314
Dynamic radar cruise control
with full-speed range ................... 302
LDA (Lane Departure Alert
with steering control) ................... 297
LKA (Lane-Keeping Assist) ........ 288
Multi-information display ..................89
Warning messages............................ 641 Do-it-yourself maintenance............. 570
Doors
Automatic door locking and
unlocking system.............................. 127
Door lock................................................. 126
Outside rear view mirrors .............. 173
Power back door ............................... 130
Rear door child-p rotectors ............ 127
Side doors ............................................... 124
Side windows ........................................ 177
Drive information .....................................93
Drive-start control .......... 193, 227, 232
Driver’s seat belt reminder light .... 636
Driver’s seat position memory.......... 162
Driving
Break-in tips ...........................................194
Correct posture .................................... 28
Driving mode select switch .......... 369
Procedures ............................................. 192
Winter drive tips ............................... 380
Driving position memory .................... 162
Memory recall function ....................165
Dynamic radar cruise control ........... 314
Dynamic radar cruise control
with full-speed range....................... 302
Dynamic Torque Control AWD
system .....................................................375D