2018 LEXUS RX450h coolant temperature

972. Instrument cluster
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Instrument cluster
RX450h_RX450hL _U_OM48F85UEngine coolant temperature gauge Displays the engine coolant temperature
Hybrid System Indicator Displays hybrid system power ou tput or regeneration level ( → P. 99)
This display changes to a tachometer depending on the drive mode, and can be set
to show the tachometer in any driv e mode on the settings display. ( → P. 108)
Outside temperature Displays the outside temperature within the range of -40°F (-40°C) to 122°F
(50°C). Low outside temperature indicator comes on when the ambient tempera-
ture is 37°F (3°C) or lower.
Multi-information display Presents the driver with a variety of vehicle data ( → P. 101)
Displays warning messages in case of a malfunction ( → P. 667)
Clock Vehicles with a navigation system:
Time displayed is linked to the analog clock on the instrument panel. ( → P. 548)
Vehicles with a Lexus Display Audio system:
Time displayed on the clock can be adju sted on of the mu lti-information dis-
play. ( → P. 108)
Speedometer
Fuel gauge
Shift position display ( → P. 246)
Odometer and trip meter ( → P. 115)1
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100 2. Instrument cluster
RX450h_RX450hL _U_OM48F85U■
Tachometer
Hybrid System Indicator switches to the tachometer when driving mode is in sport mode.
The settings of the tachometer display can be changed on of the multi-information
display. ( → P. 108)■
Engine speed
On hybrid vehicles, engine speed is precisel y controlled in order to help improve fuel
efficiency and reduce exhaust emissions etc.
There are times when the engine speed that is displayed may differ even when vehicle
operation and driving conditions are the same. ■
Brightness of the meters (d ay mode and night mode)
The brightness of the meters is changed between day mode and night mode. ●
Day mode: When the tail lights are off or when the tail lights are on but the surrounding
area is bright ●
Night mode: When the tail lights are on and the surrounding area is dark ■
Outside temperature display ●
In the following situations, the correct outside temperature may not be displayed, or the
display may take longer than normal to change:
• When stopped, or driving at low speeds (less than 12 mph [20 km/h])
• When the outside temperature has changed suddenly (at the entrance/exit of a
garage, tunnel, etc.) ●
When “ − − ” or “E” is displayed, the sy stem may be malfunctioning.
Take your vehicle to your Lexus dealer. ■
Clock settings screen (vehicles with a navigation system only)
If the clock adjustment screen is displayed continuously wh en attempting to change the
clock settings, the system may be malfunctioning.
Have the vehicle inspected by your Lexus dealer. ■
Customization
Some functions can be customized. ( → P. 108)
NOTICE ■
To prevent damage to the engine and its components●
Do not let the indicator needle of the tachometer enter the red zone, which indicates
the maximum engine speed. ●
The engine may be overheating if the engine coolant temperature gauge is in the red
zone (H). In this case, immediately stop the vehicle in a safe place, and check the
engine after it has cooled completely. ( → P. 702)

232 4-1. Before driving
RX450h_RX450hL _U_OM48F85U●
To maintain engine braking efficien cy and charging system performance
when using engine braking, do no t put the transmission in D. ( → P. 246)●
Instability happens more fr equently when descending steep or long downhill
grades. Before descending, slow down and downshift. Do not make sudden
downshifts while descending st eep or long downhill grades.●
Avoid holding the brake pedal down too long or applying the brakes too fre-
quently. This could cause the brakes to overheat and result in reduced braking
efficiency. ●
Due to the added load of the trailer, yo ur vehicle’s engine may overheat on hot
days (at temperatures over 85 ° F [30 ° C]) when driving up a long or steep
grade. If the engine coolant temperat ure gauge indicates overheating, imme-
diately turn off the air conditioning (if in use), pull your vehicle off the road and
stop in a safe spot. ( → P. 702)●
Always place wheel blocks under both the vehicle’s and the trailer’s wheels
when parking. Put the transmission in P and apply the parking brake. Avoid
parking on a slope, but if unavoidable, do so only after performing the follow-
ing:
Apply the brakes and keep them applied.
Have someone place wheel blocks under both the vehicle’s and trailer’s
wheels.
When the wheel blocks are in place, release the brakes slowly until the
blocks absorb the load.
Shift into P and apply the parking brake.
Turn off the hybrid system.●
When restarting afte r parking on a slope:
With the transmission in P, start the hybrid system. Be sure to keep the
brake pedal depressed.
Shift into a forward gear. If reversing, shift into R.
If the parking brake is in manual mode, release the parking brake.
( → P. 254)
Release the brake pedal, and slowly pull or back away from the wheel
blocks. Stop and apply the brakes.
Have someone retrieve the blocks. 1
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390 4-6. Driving tips
RX450h_RX450hL _U_OM48F85U●
Use fluids that are appropriate to the prevailing outside temperatures.
•Engine oil
• Engine/power cont rol unit coolant
• Washer fluid ●
Have a service technician inspect the condition of the 12-volt battery. ●
Have the vehicle fitted with four snow tires or purchase a set of tire chains for
the front tires. Ensure that all tires are of the specified size and the same brand, and that chains
match the size of the tires.
Perform the following according to the driving conditions: ●
Do not try to forcibly open a window or move a wiper that is frozen. Pour
warm water over the frozen area to me lt the ice. Wipe away the water imme-
diately to prevent it from freezing. ●
To ensure proper operation of the c limate control system fan, remove any
snow that has accumulated on the air inlet vents in front of the windshield. ●
Check for and remove any excess ice or snow that may have accumulated on
the exterior lights, vehicle’s roof, chassi s, around the tires or on the brakes.●
Remove any snow or mud from the bottom of your shoes before getting in the
vehicle.Winter driving tips Carry out the necessary preparations an d inspections before driving the vehi-
cle in winter. Always drive the vehicle in a manner appropriate to the prevail-
ing weather conditions.
Pre-winter preparations
Before driving the vehicle

594 7-3. Do-it-yourself maintenance
RX450h_RX450hL _U_OM48F85U* : Vehicles with sing le-beam headlightsWasher fluid
( → P. 604) • 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 ●
Make sure that the “ACCESSORY” or “I GNITION ON” on the multi-information
display and the “READY” indicator are both off. ●
Keep hands, clothing and tools away from the moving fan and engine drive belt.●
Be careful not to touch the engine, power co ntrol unit, 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. Fuel fumes are flamma-
ble. ■
When working near the electric cooling fans or radiator grille
Be sure the power switch is off.
With the power switch in ON mode, the electric cooling fans may automatically start to
run if the air conditioning is on and/ or the coolant temperature is high. ( → P. 602)■
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

6017-3. Do-it-yourself maintenance
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Maintenance and care
RX450h_RX450hL _U_OM48F85UThe coolant level is satisfactory if it is between the “FULL” and “LOW” lines on
the reservoir when the hybrid system is cold. ■
Engine coolant reservoir
Reservoir cap
“FULL” line
“LOW” line If the level is on or below the “LOW”
line, add coolant up to the “FULL”
line. ( → P. 702)
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Power control unit coolant reservoir
Reservoir cap
“FULL” line
“LOW” line If the level is on or below the “LOW”
line, add coolant up to the “FULL”
line. ( → P. 702)■
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/power control unit 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.Coolant 1
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6598-2. Steps to take in an emergency
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When trouble arises
RX450h_RX450hL _U_OM48F85U●
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 needle continually points higher than nor-
mal ●
Changes in exhaust sound ●
Excessive tire squeal when cornering ●
Strange noises related to the suspension system ●
Pinging or other noises related to the hybrid system ●
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

702 8-2. Steps to take in an emergency
RX450h_RX450hL _U_OM48F85U■
“Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” is
shown on the multi-information display
Stop the vehicle in a safe place and tu rn off the air conditioning system, and
then stop the hybrid system.
If you see steam: Carefully lift the hood after the steam subsides.
If you do not see steam: Carefully lift the hood.
After the hybrid system has
cooled down sufficiently, inspect
the hoses and radiator core (radi-
ator) 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. 96) enters the
red zone, or a loss of hybrid system power is experienced. (For example, the
vehicle speed does not increase.) ●
“Engine Coolant Temp High Stop in a Safe Place See Owner’s Manual” or
“Hybrid System Overheated Reduced Output Power” is shown on the
multi-information display. ●
Steam comes out from under the hood.
Correction procedures 1
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