Page 450 of 628

4367-3. Do-it-yourself maintenance
IS300h_EE(OM53B95E)
CAUTION
The engine compartment contains many mechanisms and fluids that may move
suddenly, become hot, or become electrically energized. To avoid death or seri-
ous injury, observe the following precautions.
When working on the engine compartment
Make sure that the “ACCESSORY” or “IGNITION ON” on the multi-infor-
mation 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 control unit, radiator, exhaust mani-
fold, 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
flammable.
Take care because brake fluid can harm your hands or eyes and damage
painted surfaces. If fluid gets on your hands or in your eyes, flush the affected
area with clean water immediately.
If you still experience discomfort, consult a doctor.
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 automati-
cally start to run if the air conditioning is on and/or the coolant temperature is
high. (P. 446)
Safety glasses
Wear safety glasses to prevent flying or falling material, fluid spray, etc. from
getting in your eyes.
NOTICE
If you remove the air cleaner filter
Driving with the air cleaner filter removed may cause excessive engine wear
due to dirt in the air.
If the fluid level is low or high
It is normal for the brake fluid level to go down slightly as the brake pads wear
or when the fluid level in the accumulator is high.
If the reservoir needs frequent refilling, it may indicate a serious problem.
Page 453 of 628
4397-3. Do-it-yourself maintenance
7
Maintenance and care
IS300h_EE(OM53B95E)
12-volt battery
P. 447
Engine compartment
Power control unit coolant res-
ervoir (P. 444)
Engine oil level dipstick
(P. 440)
Engine coolant reservoir
(P. 444)
Engine oil filler cap
(P. 441)Fuse box (P. 475)
Washer fluid tank (P. 446)
Electric cooling fans
Condenser (P. 446)
Power control unit coolant
radiator (P. 446)
Engine coolant radiator
(P. 446)1
2
3
4
5
6
7
8
9
10
Page 458 of 628
4447-3. Do-it-yourself maintenance
IS300h_EE(OM53B95E)
Engine coolant reservoir
The coolant level is satisfactory if it is between the “FULL” and “LOW”
lines on the reservoir when the hybrid system 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. 555)
Power control unit coolant reservoir
The coolant level is satisfactory if it is between the “F” and “L” lines on
the reservoir when the hybrid system 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. 555)
Coolant
1
2
3
1
2
3
Page 459 of 628

4457-3. Do-it-yourself maintenance
7
Maintenance and care
IS300h_EE(OM53B95E)
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.
“Toyota Super Long Life Coolant” is a mixture of 50% coolant and 50% deion-
ized water. (Minimum temperature: -35C [-31F])
For more details about coolant, contact any authorized Lexus dealer or repairer,
or another duly qualified and equipped professional.
If the coolant level drops within a short time of replenishing
Visually check the radiators, hoses, engine/power control unit coolant reservoir
caps, drain cock and water pump.
If you cannot find a leak, have any authorized Lexus dealer or repairer, or
another duly qualified and equipped professional, test the cap and check for leaks
in the cooling system.
CAUTION
When the hybrid system is hot
Do not remove the engine/power control unit coolant reservoir caps or water
filler cap. (P. 558)
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 pro-
tection and cooling. 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.
Page 571 of 628

5578-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53B95E)
The coolant level is satisfac-
tory if it is between the
“FULL” and “LOW” lines on
the reservoir.
Reservoir
“FULL”
“LOW”
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
Start the hybrid system and turn the air conditioning system on to
check that the radiator cooling fan operates and to check for coolant
leaks from the radiator or hoses.
The fan operates when the air conditioning system is turned on immedi-
ately after a cold start. Confirm that the fan is 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 fan may not operate in freezing temperatures.)
If the fan is not operating:
Stop the hybrid system immediately and contact any authorized
Lexus dealer or repairer, or another duly qualified and equipped pro-
fessional.
If the fan is operating:
Have the vehicle inspected at the nearest authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
If “Hybrid System Overheat” is shown on the multi-information dis-
play
Stop the vehicle in a safe place.
Stop the hybrid system and carefully lift the hood.
4
1
2
3
5
6
7
1
2
Page 572 of 628
5588-2. Steps to take in an emergency
IS300h_EE(OM53B95E)
After the hybrid system has
cooled down, inspect the hoses
and radiator core (radiator) for
any leaks.
Radiator
Cooling fans
If a large amount of coolant
leaks, immediately contact any
authorized Lexus dealer or
repairer, or another duly quali-
fied and equipped professional.
The coolant level is satisfac-
tory if it is between the “F”
and “L” lines on the reservoir.
Reservoir
“F”
“L”
Add coolant if necessary.
Water can be used in an emer-
gency if coolant is unavailable.
Start the hybrid system and check for the multi-information display.
If the message does not disappear:
Stop the hybrid system and contact any authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
If the message is not displayed:
Have the vehicle inspected at the nearest authorized Lexus dealer or
repairer, or another duly qualified and equipped professional.
3
1
2
4
1
2
3
5
6
Page 573 of 628

5598-2. Steps to take in an emergency
8
When trouble arises
IS300h_EE(OM53B95E)
CAUTION
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 hood, do not open the hood until the
steam has subsided. The engine compartment may be very hot.
After the hybrid system has been turned off, check that the “READY” indica-
tor is off.
When the hybrid system operating, the gasoline engine may automatically
start, or the cooling fan may suddenly operate even if the gasoline engine
stops. Do not touch or approach rotating parts such as the belt and fan, which
may lead to fingers or clothing (especially a tie, a scarf or a muffler) getting
caught, resulting in serious injury.
NOTICE
When adding engine/power control unit coolant
Add coolant slowly after the hybrid system has cooled down sufficiently. Add-
ing cool coolant to a hot hybrid system too quickly can cause damage to the
hybrid system.
To prevent damage to the cooling system
Observe the following precautions:
Avoid contaminating the coolant with foreign matter (such as sand or dust
etc.).
When using coolant additives, use genuine Toyota products or equivalent.
Do not loosen the coolant reservoir caps
or water filler cap while the hybrid sys-
tem and radiator are hot.
High temperature steam or coolant could
spray out.