Toyota MZ engine

The Toyota MZ engine family is a piston V6 engine series. It was the successor to the previous VZ engine family, and was Toyota's second V6 engine series. It is a lightweight V6 engine of an all-aluminium design, using lightweight parts than the previous heavy-duty VZ block engines in an effort to lower production costs and decrease engine and reciprocating weight without sacrificing reliability.
Toyota sought to enhance the drivability pattern of the engine at exactly 3000 rpm, since that was the typical engine speed for motors cruising on the highway. The result was less cylinder distortion coupled with the decreased weight of rotating assemblies, smoother operation at that engine speed, and increased engine efficiency.
The MZ series has an aluminium engine block and aluminium alloy DOHC cylinder heads. The cylinders are lined with cast iron, and is of a closed deck design. The engine is a 60 degree V6 design. It uses multi-port fuel injection, four valves per cylinder, a one-piece cast camshaft and a cast aluminium intake manifold.
This engine has been phased out in most markets, replaced by variants of the then-new GR series.

1MZ-FE

The 1MZ-FE is a dual overhead cam V6 engine, replacing the 3VZ-FE as the standard 3.0 L V6 engine in North America and later worldwide. Bore and stroke is. Output is at 5,200–5,400 rpm with of torque at 4,400 rpm. Horsepower ratings dropped after the Society of Automotive Engineers implemented a new power measurement system for vehicle engines; Toyota engines rated on 87 octane dropped the most, compared to the same engines used by Lexus rated on 91octane. It has bucket tappets and was designed for good fuel economy of city and highway without an overall performance trade-off.
Toyota Racing Development offered a factory supported bolt-on supercharger kit for the MY1997–2000 Camry, MY1998–2000 Sienna and MY1999–2000 Solara in North America. Power output was bumped to and of torque.
The 1MZ-FE was on Ward's 10 Best Engines list for 1996.
Applications:

1994–2002 Toyota Camry
2002–2006 Toyota Camry (MCV36R)
1994–2003 Lexus ES 300 and Toyota Windom
1994–2004 Toyota Avalon and 2000 Toyota Pronard
1997-2003 Toyota Harrier
1997–2002 Toyota Sienna
1997–2001 Toyota Mark II Wagon
1998–2003 Toyota Camry Solara
2000–2005 Toyota Estima/Toyota Tarago/Toyota Previa

Beginning in 1998, VVT-i was added. This increased the output to at 5800 rpm and of torque at 4400 rpm. It was used on later models of the Avalon, Sienna and Camry. When installed in the Highlander, power was ; torque and engine speeds did not change. Early versions of the 1MZ-FE with VVT-i used a dual throttle body while later versions used a drive by wire system. It also contains an EGR block off plate on the exhaust manifolds.
Applications:

1998–2003 Lexus RX 300
1999–2003 Lexus ES 300
2000–2004 Toyota Avalon
2000–2003 Toyota Highlander/Kluger
2001–2003 Toyota Sienna
2002–2008 Toyota Alphard
2003–2006 Toyota Camry

2MZ-FE

The 2MZ-FE is a V6 engine, replacing the 4VZ-FE as the worldwide 2.5 L V6 engine. Bore and stroke is. Output is at 6000 rpm with torque of at 4600 rpm.
Applications:

1996-2001 Toyota Camry
1996-2001 Toyota Windom
1997–2001 Toyota Mark II Qualis

3MZ-FE

The 3MZ-FE is a version. Bore and stroke is. Output is with of torque in the Camry and with of torque in the Sienna and Highlander. It also features VVT-i, ETCS-i, PA6 plastic intake, and increased throttle body diameter over the 1MZ. The 3MZ uses a new flat-type knock sensor, which is a departure from the typical resonator type knock sensor used on the previous MZs. Previous MZs had poor knock control, or perhaps oversensitivity when detecting knock, and power loss up to may be realized due to erratic ignition timing when using an octane lower than 91. The new flat-type knock sensor is a completely different design and detects more frequencies than the traditional resonator type. This provides the ECU with more accurate data. A bolt goes through the center of the knock sensor, which then mates the sensor to the block on each bank.
Applications:

2004-2007 Toyota Highlander
2004–2008 Toyota Camry Solara
2004–2006 Toyota Sienna
2004–2006 Toyota Camry (XV30)
2005–2010 Toyota Highlander Hybrid
2004–2006 Lexus RX 330
2006–2008 Lexus RX 400h
2004–2006 Lexus ES 330
2006-2014 Mitsuoka Orochi

Excessive oil consumption issues

The MZ engines are notorious for excess oil consumption, otherwise known as "oil gelling" or "engine sludge". This is caused by several factors, including problems with the engine's PCV system, worn-off parts, or a bad or leaking valve cover gasket. This allowed oil to leak into the engine bay, with symptoms ranging from blue-grey smoke, bad spark plugs and sludge buildup in cylinder bank 2, to low compression on the second cylinder. This issue is widespread in many MZ engines produced, especially in later models, and as such affected many vehicles that used this engine in their configurations. It is very important to the life of these engines that oil changes should be done on a regular basis. A class action lawsuit was filed because of this problem. This particular issue remains a significant concern for MZ engines of that era.