2019 LEXUS RX350 cooling

5917-3. Do-it-yourself maintenance
7
Maintenance and care
RX350/RX350L_U * : Vehicles with single-beam headlightsTire inflation pres-
sure (  P. 613) • Tire pressure gauge • Compressed air source
Washer fluid
(  P. 603) • Water or washer fluid containing antifreeze (for winter use)
• Funnel (used only for adding water or washer fluid)
WARNING
The engine compartment contains many mechan isms and fluids that may move suddenly,
become hot, or become electrically energize d. To avoid death or serious injury, observe
the following precautions. ■
When working on the engine compartment ●
Keep hands, clothing and tools away from the moving fan and engine drive belt.●
Be careful not to touch the engine, radiator, exhaust manifold, etc. right after driving
as they may be hot. Oil and other fluids may also be hot. ●
Do not leave anything that may burn easily, such as paper and rags, in the engine
compartment. ●
Do not smoke, cause sparks or expose an open flame to fuel or the battery. Fuel and
battery fumes are flammable. ●
Be extremely cautions when working on the battery. It contains poisonous and corro-
sive sulfuric acid. ■
When working near the electric cooling fans or radiator grille
Be sure the engine switch is off.
With the engine switch in IGNITION ON mode, the electric cooling fans may auto-
matically start to run if the air conditioning is on and/or the coolant temperature is high.
(  P. 599) ■
Safety glasses
Wear safety glasses to prevent flying or falling material, flui d spray, etc. from getting in
your eyes.
NOTICE ■
If you remove the air cleaner filter
Driving with the air cleaner f ilter removed may cause excessive engine wear due to dirt
in the air. Items Parts and tools

594 7-3. Do-it-yourself maintenance
RX350/RX350L_UEngine 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
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4 5
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598 7-3. 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 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 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.

6918-2. Steps to take in an emergency
8
When trouble arises
RX350/RX350L_U WARNING ■
When replacing the battery ●
When the vent plug and indicator are close to the hold down clamp, the battery fluid
(sulfuric acid) may leak. ●
For information regarding battery repl acement, contact your Lexus dealer.
NOTICE ■
When handling jumper cables
When connecting the jumper cables, ensure that they do not become entangled in the
cooling fans or engine drive belt.

692 8-2. Steps to take in an emergency
RX350/RX350L_U 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, 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 capIf 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
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4

6938-2. Steps to take in an emergency
8
When trouble arises
RX350/RX350L_U Add coolant if necessary. Water can be used in an emergency if
coolant is unavailable.
Start the engine and turn the air conditio ning 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 operating 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
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694 8-2. 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.

702 9-1. Specifications
RX350/RX350L_U * : The coolant capacity is a reference quantity.
If replacement is necessary, contact your Lexus dealer.Cooling system Capacity
* 
RX350 (Vehicles with out towing package)
9.5 qt. (9.0 L, 7.9 Imp. qt.) 
RX350 (Vehicles with towing package)
10.5 qt. (9.9 L, 8.7 Imp. qt.) 
RX350L
13.1 qt. (12.4 L, 11 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
(Turn the engine switch off and turn on the head-
lights for 20 to 30 seconds.)
Charging rates 5 A max.