Page 1 of 2000

ENGINE - 2AZ-FE ENGINE EG-4
FEATURES OF 2AZ-FE ENGINE
The 2AZ-FE engine has achieved the following performance through the use of the items listed below.
(1) High performance and reliability
(2) Low noise and vibration
(3) Lightweight and compact design
(4) Good serviceability
(5) Clean emission and fuel economy
Section
Item(1)(2)(3)(4)(5)
Engine
A cylinder block made of aluminum alloy along with a
magnesium alloy die-cast cylinder head cover is used.
Engine
ProperA taper squish shape is used for the combustion chamber.p
A resin gear balance shaft is used.
Vl
A timing chain and chain tensioner are used.
Va l v e
MechanismThe shim-less type valve lifters are used.MechanismThe VVT-i system is used.
A chacoal filter is used in the air cleaner cap.
Intake andIntake manifold made of plastic is used.Intake and
ExhaustThe linkless-type throttle body is used.
SystemA thin-wall ceramic TWC (Three-Way Catalytic converter)
is used.
The fuel returnless system is used.
Fuel
System
Quick connectors are used to connect the fuel hose with the
fuel pipe.
System12-hole type fuel injectors with high atomizing performance
are used.
Ignition
SystemIridium-tipped spark plugs are used.
Charging
SystemThe segment conductor type generator is used.
Starting
SystemPS (Planetary reduction-Segment conductor motor) type
starter is used.
The ETCS-i is used.
Engine
Control
The DIS (Direct Ignition System) makes ignition timing
adjustment unnecessary.
Control
SystemThe non-contact type sensor is used in the throttle position
sensor.
The planar type air-fuel ratio sensor is used.
Page 2 of 2000
ENGINE - 2AZ-FE ENGINE
DR011EG20
Cylinder Head Cover
Cylinder Head Cover Gasket
02AEG02Y 02AEG01Y
Cylinder
Bore Side
FrontOuter
Side
Shim A
A
A - A Cross SectionEG-5
ENGINE PROPER
1. Cylinder Head Cover
A lightweight magnesium alloy die-cast
cylinder head cover is used.
Acrylic rubber, which excels in heat resistance
and reliability, is used for the cylinder head
cover gasket.
2. Cylinder Head Gasket
A steel-laminate type cylinder head gasket is used. A shim has been added around the cylinder bore to
increase the sealing surface, thus improving the sealing performance and durability.
Page 3 of 2000
ENGINE - 2AZ-FE ENGINE
208EG67 DR011EG21
Exhaust Side
Intake Side A A
A - A Cross Section Injector
IN
EX
Bypass
Passage
Ta p e r S q u i s h EG-6
3. Cylinder Head
Through the adoption of the taper squish combustion chamber, the engine knocking resistance and fuel
efficiency have been improved.
An upright intake port is used to improve the intake efficiency.
Installing the injectors in the cylinder head enables the injectors inject fuel as close as possible to the
combustion chamber. This prevents the fuel from adhering to the intake port walls, which reduces HC
exhaust emissions.
The routing of the water jacket in the cylinder head has been optimized to realize the high cooling
performance. In addition, a water bypass passage has been provided below the exhaust ports to reduce the
number of parts and the weight.
Page 4 of 2000

ENGINE - 2AZ-FE ENGINE
DR011EG22 01NEG26Y
Air Flow During Engine Revolution
Wa t e r P u m p
Swirl Chamber
Crankshaft
Bearing Cap
Plastic Region
Tightening BoltsThermostat Housing
Air Conditioning
Compressor BracketsAir Passage Holes
Air Flow
NOTICE
Never attempt to machine the cylinder because it has a thin liner thickness.
EG-7
4. Cylinder Block
Lightweight aluminum alloy is used for the cylinder block.
By producing the thin cast-iron liners and cylinder block as a unit, compaction is realized.
Air passage holes are provided in the crankshaft bearing area of the cylinder block. As a result, the air at
the bottom of the cylinder flows smoother, and pumping loss (back pressure at the bottom of the piston
generated by the piston’s reciprocal movement) is reduced to improve the engine’s output.
The oil filter and the air conditioning compressor brackets are integrated into the crankcase. Also, the
water pump swirl chamber and thermostat housing are integrated into the cylinder block.
Page 6 of 2000
ENGINE - 2AZ-FE ENGINE
01MEG01Y
Taper Squish Shape : Resin Coating
240EG45
Plastic Region Tightening BoltsEG-9
5. Piston
The piston is made of aluminum alloy and skirt area is made compact and lightweight.
The piston head portion uses a taper squish shape to improve the fuel combustion efficiency.
The piston skirt has been coated with resin to reduce the friction loss.
6. Connecting Rod
The connecting rods and caps are made of
high-strength steel for weight reduction.
Nut-less type plastic region tightening bolts are
used on the connecting rod for a lighter design.
The connecting rod bearings are reduced in
width to reduce friction.
Page 7 of 2000
ENGINE - 2AZ-FE ENGINE
01NEG31Y
No.1 JournalBalance Shaft Drive Gear
Oil Hole
Crank Pin
Balance Weight
01NEG32Y
: Resin Gear
Balance Shaft
HousingBalance Shaft No.1 Balance Shaft No.2Crankshaft
Balance Shaft Drive Gear EG-10
7. Crankshaft
The forged crankshaft has 5 journals and 8 balance weights.
The crankshaft is made of forged steel.
Pin and journal fillets are roll-finished to maintain adequate strength.
The balance shaft drive gear is provided for the crankshaft.
8. Balance Shaft
General
A balance shaft is used to reduce vibrations.
The crankshaft directly drives the No. 1 balance shaft.
In addition, a resin gear is used on the driven side to suppress noise and offer lightweight design.
Page 13 of 2000
ENGINE - 2AZ-FE ENGINE
01NEG35Y
Throttle Body
To H e a t e r C o r e
To R a d i a t o r
Thermostat
From Radiator Wa t e r P u m pBypass Passage
01NEG59Y
Bypass PassageCylinder Head
Wa t e r P u m p
Cylinder Block
Thermostat
Reservoir
Ta n k
RadiatorThrottle
BodyHeater Core EG-16
COOLING SYSTEM
The cooling system uses a pressurized forced-circulation system with pressurized reservoir tank.
A thermostat with a bypass valve is located on the water inlet housing to maintain suitable temperature
distribution in the cooling system.
An aluminum radiator core is used for weight reduction.
The flow of the engine coolant makes a U-turn in the cylinder block to ensure a smooth flow of the engine
coolant. In addition, a bypass passage is enclosed in the cylinder head and the cylinder block.
Warm water from the engine is sent to the throttle body to prevent freeze-up.
The TOYOTA genuine Super Long Life Coolant (SLLC) is used.
System Diagram
Page 15 of 2000
ENGINE - 2AZ-FE ENGINE
01MEG32Y
Exhaust ManifoldIntake ManifoldMain Muffler
Sub Muffler
TWC
Air Cleaner TWC EG-18
INTAKE AND EXHAUST SYSTEM
1. General
The linkless-type throttle body is used to realize excellent throttle control.
ETCS-i (Electronic Throttle Control System-intelligent) is used to provide excellent throttle control. For
details, see page EG-43.
A plastic intake manifold is used for weight reduction.
A stainless steel exhaust manifold is used for weight reduction.