The Toyota AZ engine family is a straight-4 piston engine series. The AZ series uses an aluminium engine block with cast iron cylinder liners and aluminium DOHC cylinder head. The engine series features many advanced technologies including slant-squish combustion chambers, offset cylinder and crank centers, and the VVT-i continuously variable intake valve timing system. The aluminium engine measures 626 mm long, 608 mm wide, and 681 mm tall. The cylinder block is an open-deck, midi-skirt die-cast aluminium type with cast-in iron liners and a die-cast aluminium lower crankcase and a stamped oil pan. The forged steel crankshaft is fully balanced with eight counterweights and supported by five main bearings. A helical gear pressed in No. 3 counterweight drives twin contra-rotating balance shafts in the shaft housing within the lower crankcase. The dual overhead camshafts are driven by a single-stage roller chain of 8 mm pitch, enabling a narrow included valve angle of 27.5°. The camshafts act on four valves per cylinder via bucket tappets. As in the recent Toyota engine practice, no clearance adjusting shim is employed. Valve diameters are 34 mm for intake and 29.5 mm for exhaust, with 8 mm lift for both intake and exhaust. The four-vane VVT-i device is fitted on the intake camshaft, altering timing by 50°. The valve cover is made of magnesium to save weight. Fuel is injected sequentially via an ultra-fine-atomization injector with twelve small injection holes, each 0.18 mm in diameter. As in the smaller NZ engine, the new AZ adopts a plastic, built-up, and vibration-welded intake manifold integrating a large volume plenum chamber (3.5 L volume including a 1.3 L resonator). Exhaust manifolds are of tubular construction with integrated catalytic converters. The AZ is the replacement for the S engine. Its successor is the AR engine.

Excessive oil consumption

The 2AZ-FE engine in the 2007-2009 Camry and 2006-2009 Rav4 may burn excessive oil and is involved in this lawsuit. Other engines are also affected. If this Toyota engine is burning more than 1 USqt of oil in 1200 mi, has less than 150000 mi, is less than 10 years old, and is located in the U.S., Toyota service will perform a free oil consumption test to determine if the engine is affected. There are approximately 1,715,200 vehicles covered by this Warranty Enhancement Program. A similar campaign are also done in Japan by Toyota in 2014.

1AZ

The 1AZ line of engines have 1998 cc displacements.

1AZ-FE

The 1AZ-FE is a 1998 cc version. Output is 108 kW at 6000 rpm with 190 Nm of torque at 4000 rpm for the Camry Aurion version. Rav4 and Ipsum engines were rated at 148-150 hp at 6000 rpm and 142 lbft of torque at 4000 rpm. The 1AZ has a total displacement of 1998 cc with 86x86 mm bore and stroke, and a compression ratio of 9.6:1.

1AZ-FSE

The 1AZ-FSE is a 1998 cc version. Bore and stroke is 86x86 mm, and a compression ratio of 11.0:1. Output is 149 PS at 5700 rpm with 196 Nm of torque at 4000 rpm. The 1AZ-FSE features Toyota's D-4 direct injection system.

2AZ

The 2AZ line of engines have 2362 cc displacements.

2AZ-FE

The 2AZ-FE is a 2362 cc version built in Japan (Kamigo Plant and by Toyota Industries Corporation), at TMMK in the USA and also built in China for select Scion xB models, and also in Australia, obtains a total displacement of 2362 cc with 88.5x96 mm bore and stroke, with a compression ratio of 9.6:1. Output is 160 hp at 5600 rpm; 220 Nm of torque at 4000 rpm. Later versions of the 2AZ-FE engine were upgraded with 9.8:1 compression ratio, a slightly more aggressive intake cam profile, 6500 rpm redline, and piston oil squirters. These later versions are rated at 161 hp in the Scion tC, 177 hp in the RAV4, and 158 hp in the Camry, Corolla XRS, Scion xB, and 177 hp for the Previa/Estima/Alphard. Japan-made Toyota vehicles with the 2AZ-FE engine were equipped with the K112 transmission also referred to as 7-speed Super CVT-i automatic (Seven-speed Sequential Shiftmatic) from October 2005. However, these later 2AZ-FE models were the first to be rated under the new SAE J1349 standard. The new standard usually produces more conservative numbers, though no definitive comparison is available since the two versions were never tested by the same standard. The RAV4 uses a different timing chain cover from the Camry, they can however be interchanged. A TRD supercharger was available for the Scion tC and 2nd generation xB until Spring 2009. There have been complaints of this engine "burning oil" in North America, with the issue starting after 45000 mi, though mostly after 60000-75000 mi. Piston ring design has been identified as a potential problem. Toyota has issued a TSB (Technical service bulletin) TSB #0094-11 in August 2011 but has not issued a recall. Alternative theories point to a head gasket problem: the 2AZ-FE aluminum block threads may wear out on the back three middle bolts (closest to firewall). Check TSB SB-0015-11. There are several class-action lawsuits underway regarding this issue. In January 2015, Toyota North America issued extended warranty notification (ZE7) for this issue for Toyota North America vehicles only.

2AZ-FSE

The 2AZ-FSE is a 2362 cc version. Bore and stroke is 88.5x96 mm, and a compression ratio of 11.0:1. Output is 163 PS at 5800 rpm with 231 Nm of torque at 3800 rpm. The 2AZ-FSE features Toyota's D-4 direct injection system.

2AZ-FXE

The 2AZ-FXE is an Atkinson cycle variant of the 2AZ-FE. It has the same bore and stroke, but the intake cam and pistons are unique. It has a physical compression ratio of 12.5:1. The longer than normal open intake valve duration leads to a reduction in cylinder charge and reduced torque and power output, but efficiency is increased. This combination makes the 2AZ-FXE suitable for use only in hybrid vehicles, where peak torque and power demands can be met by the electric motor and battery. Maximum output when used in the Camry hybrid is 211 hp at 6000 rpm with 257 Nm of torque at 4400 rpm.