2010 Lexus HS250h engine

5
When trouble arises
543
5-2. Steps to take in an emergency
After the hybrid system has cooled
down, check the power control
unit coolant level and inspect the
cooling system for leaks.
Add power control unit coolant if
nec
essary.
Water can be used in an emer -
gency if power control unit coolant
is una
vailable. ( P. 5 5 2 )
Have the vehicle inspected at the ne arest Lexus dealer as soon as possi-
ble.
■Overheating
The following symptoms may occur wh en
your vehicle is overheating:
●The high engine coolant temperature warn ing light comes on or flashes, or the
hybrid system output decreases.
●Steam comes out from the engine area.
●“HYBRID SYSTEM OVERHEAT” is displayed on the multi-information display.

544
5-2. Steps to take in an emergency
CAUTION
■To prevent an accident or injury when inspecting under the hood of your vehicle
●If steam is seen coming from under the hood, do not open the hood until the
steam has subsided. The engine compartm ent may be very hot, causing serious
injuries such as burns.
●Check that the indicator on the “POWER ” switch and the READY indicator are
off.
●For vehicles with a hybrid system, there are times when the gasoline engine auto-
matically starts to run or the cooling fans suddenly start to operate. Do not touch
or approach the rotating parts of the belt or fans. Doing so may lead to fingers,
clothes or tools getting caught, resulting in injury.
●Do not loosen the coolant reservoir cap while the hybrid system and radiator are
hot. 
Serious injuries, such as burns, may resu lt from hot coolant and steam released
under pressure.
NOTICE
■When adding engine/power control unit coolant
Wait until the hybrid system has cooled down before adding engine/power control
unit coolant. 
When adding coolant, do so slowly. Adding cool coolant to a hot hybrid system too
quickly can cause damage to the hybrid system.

549
6-1. Specifications
6
Vehicle specifications
This number is also on the Certifi-
cation Label.
■ Engine number and electric motor (tr
action motor) number
The numbers are stamped on the locations shown in the above illustration.
Engine
Model2AZ-FXE
Ty p e4-cylinder in line, 4-cycle, gasoline
Bore and stroke3.48 3.78 in. (88.5  96.0 mm)
Displacement144.1 cu.in. (2362 cm3)
Drive belt tensionAutomatic adjustment
Valve clearance
(engine cold)Intake: 0.007  0.011 in. (0.19  0.29 mm) 
Exhaust: 0.015
 0.019 in. (0.38  0.48 mm)

551
6-1. Specifications
6
Vehicle specifications
■Engine oil selection
“Toyota Genuine Motor Oil” is used in y
our Lexus vehicle. Use Lexus
approved “Toyota Genuine Motor Oil” or equivalent to satisfy the follow-
ing grade and viscosity.
Oil grade: ILSAC multigrade engine oil
Recommended viscosity: SAE 0W-20
SAE 0W-20 is the best choice for
good fuel economy and good
star

ting in cold weather.
If SAE 0W-20 is not available,
S
AE 5W-20 oil may be used.
However, it must be replaced with
SAE 0W-20 at the next oil
change.
The 0W portion of the oil viscosity rating indicates the characteristic of the oil
which allows cold startability. Oils wi th a lower value before the W allow for
easier starting of the engine in cold weather.
The 20 in 0W-20 indicates the oil viscosity when the oil is at its operating
temper
ature. An oil with a higher viscosity may be better suited if the vehicle
is operated at high speeds, or under extreme load conditions.
How to read oil container label:
The ILSAC (International Lubricant St andar
dization and Approval Com-
mittee) Certification Mark is added to some oil containers to help y
ou
select the oil you should use.
Outside temperature

552
6-1. Specifications
Cooling system
Ignition system
CapacityGasoline engine
Power control unit
7.7 qt. (7.3 L, 6.4 Imp. qt.)
3.1 qt. (2.9 L, 2.6 Imp. qt.)
Coolant type
Use either of the following.• “Toyota Super Long Life Coolant”
• A 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.
Spark plug
Make 

GapDENSO SK20R11 
NGK IFR6A11 
0.043 in. (1.1 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust spark plug gap.

557
6-1. Specifications
6
Vehicle specifications
Fuel information
■Fuel tank opening for unleaded gasoline
To help prevent incorrect fueling, your vehicle has a fuel tank opening that only
a
ccommodates the special nozzle on unleaded fuel pumps.
■Gasoline quality
In very few cases, driveability problems may be caused by the brand of gasoline you
ar
e using. If driveability problems persist, try changing the brand of gasoline. If this
does not correct the problem, consult your Lexus dealer.
■Gasoline quality standards
●Automotive manufacturers in the U.S.A., Europe and Japan have developed a
specification for fuel quality called the World-Wide Fuel Charter (WWFC),
which is expected to be applied worldwide.
●The WWFC consists of four categories that are based on required emission
levels. In the U.S., category 4 has been adopted.
●The WWFC improves air quality by lowering emissions in vehicle fleets, and
improves customer satisfaction through better performance.
■Recommendation of the use of gasoline containing detergent additives
●Lexus recommends the use of gasoline that contains detergent additives to
avoid the build-up of engine deposits.
●All gasoline sold in the U.S.A. contains detergent additives to clean and/or keep
clean intake systems.
You must only use unleaded gasoline in your vehicle. 
Select octane rating 87 (Research Octane Number 91) or higher. Use of
unlead

ed gasoline with an octane rating lower than 87 may result in engine
knocking. Persistent knocking can lead to engine damage.
At minimum, the gasoline you use should meet the specifications of
ASTM D4814 in the U.S.A. an d CGSB3.5-M93 in Canada.

558
6-1. Specifications
■Recommendation of the use of cleaner burning gasoline
Cleaner burning gasoline, including reformulated gasoline that contains oxygen-
ates such as ethanol or MTBE (Methyl Tertiary Butyl Ether) is available in many
areas.
Lexus recommends the use of cleaner burning gasoline and appropriately blended
reformulated gasoline. These types of gasoline provide excellent vehicle perfor-
mance, reduce vehicle emissions and improve air quality.
■Non-recommendation of the use of blended gasoline
●Lexus allows the use of oxygenate blended gasoline where the oxygenate con-
tent is up to 10% ethanol or 15% MTBE.
●If you use gasohol in your vehicle, be sure that it has an octane rating no lower
than 87.
●Lexus does not recommend the use of gasoline containing methanol.
■Non-recommendation of the use of gasoline containing MMT
Some gasoline contains an octane enhancing additive called MMT (Methylcyclo-
pentadienyl Manganese Tricarbonyl).
Lexus does not recommend the use of gasoli ne that contains MMT. If fuel contain-
ing MMT is used, your emission control system may be adversely affected.
The malfunction indicator lamp on the instrument panel may come on. If this hap-
pens, contact your Lexus dealer for service.
■If your engine knocks
●Consult your Lexus dealer.
●You may occasionally notice light knocking for a short time while accelerating
or driving uphill. This is normal and there is no need for concern.

559
6-1. Specifications
6
Vehicle specifications
NOTICE
■Notice on fuel quality
●Do not use improper fuels. If improper fuels are used, the engine will be dam-
aged.
●Do not use leaded gasoline. 
Leaded gasoline can cause damage to your vehicle’s three-way catalytic convert-
ers causing the emission control system to malfunction.
●Do not use gasohol other than the type previously stated. 
Other gasohol may cause fuel system damage or vehicle performance problems.
●Using unleaded gasoline with an octane number or rating lower than the level
previously stated will cause persistent heavy knocking. 
At worst, this will lead to engine damage.
■Fuel-related poor driveability
If poor driveability is encountered after using a different type of fuel (poor hot start-
ing, vaporization, engine knoc king, etc.), discontinue the use of that type of fuel.
■When refueling with gasohol
Take care not to spill gasohol. It can damage your vehicle’s paint.