2008 LEXUS RX400H engine

5
When trouble arises
421
5-2. Steps to take in an emergency
RX400h_U
If the 12-volt battery is discharged
The following procedures may be used to start the hybrid system if the vehi-
cle’s battery is discharged.
You can call your Lexus dealer, or qualified repair shop.
If you have a set of jumper (or booster) cables and a second vehicle
with a 12-volt battery, you can jump start your Lexus following the steps
below.Remove the engine compartment cover.
(→ P. 3 1 7 )
Connecting the jumper cables.
If required, remove all vent plugs from the booster battery. Lay a
cloth over the open vents on the booster battery. (This helps reduce
the explosion hazard, personal injuries and burns.)
Positive (+) battery terminal on your vehicle
Positive (+) battery terminal on the second vehicle
Negative (-) battery terminal on the second vehicle
Connect the jumper cable to ground on your vehicle as shown in the
illustration. Start the hybrid system of the second vehicle. Increase the gas-
oline engine speed slightly and maintain at that level for
approximately 5 minutes to recharge the battery of your vehi-
cle.
Maintain the gasoline engine speed on the second vehicle and
start the vehicle’s hybrid system.
STEP1
STEP2
STEP3
STEP4

424
5-2. Steps to take in an emergency
RX400h_U
If your vehicle overheats
■Electric motor (traction motor) and inverter
If the message WATER TEMP is displayed on the multi-information
display.
■ Gasoline engine
If the needle of the engine coolant temperature gauge enters the
red zone, the gasoline engine has probably overheated.
Observe the following steps:
Stop the vehicle in a safe place and turn off the automatic air
conditioning system.
Check to see if steam is coming out from under the hood.
If you see steam: Stop the hybrid system. Carefully lift the hood after the
steam subsides and then restart the hybrid system.
If you do not see steam: Leave the hybrid system running and carefully lift the hood.
Check to see if the cooling fan is operating.
If the fan is operating: Wait until the temperature of the engine (shown on the
instrument cluste r) begins to fall and then stop the hybrid
system.
If the fan is not operating: Stop the hybrid system immediately and call your local
Lexus dealer.
After the hybrid system has
cooled down sufficiently, check
the engine coolant level and
inspect the radiator core (radia-
tor) for any leaks.
STEP1
STEP2
STEP3
STEP4

5
When trouble arises
425
5-2. Steps to take in an emergency
RX400h_U
■Overheating
If you observe the following, your vehicle may be overheating.
●The message WATER TEMP is displayed on the multi-information display.
●The engine coolant temperature gauge enters the red zone or a loss of power is
experienced.
●Steam is coming from under the hood.
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 compartment may be very hot, causing serious
injury such as burns.
●Keep hands and clothing away from the fan and other belts while the hybrid sys-
tem is running.
●Do not loosen the radiator cap while the hybrid system and radiator are hot.
Serious injury, such as burns, may result from hot coolant and steam released
under pressure.
Add engine coolant if required.
Water can be used in an emer-
gency measure if engine coolant
is unavailable. (→P. 4 3 5 )
Have the vehicle checked at your nearest Lexus dealer as soon as pos-
sible.
STEP5

426
5-2. Steps to take in an emergency
RX400h_U
NOTICE
■When adding engine coolant
Wait until the engine has cooled down before adding engine coolant.
When adding coolant, do so slowly. Adding cool coolant to a hot engine too quickly
can cause damage to the hybrid system.

432
6-1. Specifications
RX400h_U■
Gasoline engine number and electr ic motor (traction motor) num-
ber
The gasoline engine number and tr action motor number are stamped
as shown.
Gasoline engine number
Electric motor (traction motor)
number
Engine
Model3MZ-FE
Ty p e6-cylinder V type,
4-cycle, gasoline
Bore and stroke3.62 × 3.27 in.
(92 × 83 mm)
Displacement202.1 cu.in.
(3311 cm3)
Drive belt tensionAutomatic adjustment
Valve clearance (engine cold)
Intake:
0.006 
0.010 in. (0.15  0.25 mm)
Exhaust:
0.010 
0.014 in. (0.25  0.35 mm)

434
6-1. Specifications
RX400h_U
Lubrication system
Oil viscosity
● The 0W portion of the oil viscosity rating indicates the characteristic of
the oil which allows cold startability. Oils with 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
temperature. An oil with a higher viscosity may be better suited if the
vehicle is operated at high speeds, or under extreme load condition.
Oil capacity
drain and refill
(reference)
Wi th f il ter5.0 qt. (4.7 L, 4.1 lmp.qt.)
Without filter4.8 qt. (4.5 L, 4.0 lmp.qt.)
Oil gradeILSAC multi-grade engine oil
Recommended oil
viscosity
Use Lexus approved “Toyota Genuine Motor Oil” or
equivalent to satisfy the grade and viscosity shown
below.
0W-20 is an oil that provides optimal levels of fuel
efficiency.
Outside temperature

435
6-1. Specifications
6
Vehicle specifications
RX400h_U
Cooling system
Ignition system
Capacity
Gasoline engine
power control unit10.9 qt. (10.3 L, 9.0 Imp.qt.)
3.6 qt. (3.4 L, 3.0 Imp.qt.)
Coolant type
Use either of the following.• “Toyota Super Long Life Coolant”
• Similar high-quality ethylene glycol-based non-sili-cate, non-amine, non-nitrite, and non-borate cool-
ant with long-life organic acid technology
Do not use plain water alone.
Spark plug
Make
DENSO
NGK
Gap
SK20R11
IFR6A11
0.043 in. (1.1 mm)
NOTICE
■Iridium-tipped spark plugs
Use only iridium-tipped spark plugs. Do not adjust gap when tuning the gasoline
engine.

436
6-1. Specifications
RX400h_U
Electrical system
12-volt battery
Open voltage at
68°F (20 °C):12.6  12.8 V Fully charged
12.2 
12.4 V Half charged
11.8 
12.0 V Discharged
(Voltage checked 20 minutes after the
key is removed from the engine switch
with all the lights turned off)
Charging rates5 A max.