Toyota 1MZ-FE 3.0L Engine Specs, Problems & Reliability
The 1MZ-FE is a 3.0-liter V6 gasoline engine produced by Toyota from 1993 to 2007 as a replacement for the 3VZ-FE. Back in the day, this engine was widely used in the Toyota Camry, Avalon, Highlander, and some Lexus models. During the last years of production, the 1MZ was gradually moved out by a 3.3-liter engine from the same MZ family - 3MZ-FE.
The MZ series features a lightweight aluminum cylinder block with a 60-degree V6 design and press-fitted cast-iron cylinder liners. The engine block is equipped with the forged crankshaft with four main journals, forged connecting rods, and aluminum alloy pistons (resin coating for piston skirts was applied for VVT-i version). The 1MZ-FE has aluminum cylinder heads with four valves per cylinder and dual overhead camshafts. The exhaust camshafts are driven by a timing belt, while gears on the exhaust camshafts drive the intake camshafts.
The intake valve diameter is 34.0 mm; exhaust valve diameter - 27.3 mm; valve stem diameter for both is 5.5 mm. The engine was offered in non-VVT-i and VVT-i versions. 1MZ camshaft specifications for the non-VVT-i series: duration - 228/228 deg (intake/exhaust), valve lift 7.85/7.60 mm (intake/exhaust). VVT-i engines have intake duration of 236 degrees and exhaust duration of 236 degrees. There are not hydraulic lifters in the valvetrain. Valve adjustment is necessary every 60-80k miles (100,000-150,000 km).
The 1MZ-FE engine uses multi-port fuel injection (MFI) and has an aluminum intake manifold with Toyota's Acoustic Control Induction System (ACIS) - variable length intake manifold. The ACIS, depending on the application, is a two-stage system (Camry, Avalon, and etc.) or a three-stage system (Lexus ES 300). The electronically controlled ignition (DIS) has six individual coils. Each coil is fitted over a spark plug (coil-on-plug). Non-VVT-i 1MZ engines had exhaust gas recirculation system (EGR), while VVT-i engines got EGR block off plates on the exhaust manifolds. All MZ engines use stainless steel exhaust manifolds.
Engine Specs
Toyota Motor Manufacturing Kentucky
0.2 l (0.21 qt) - oil filter
1MZ Engine Problems and Reliability
The 1MZ is known as a convenient Toyota's engine, famous for incredible reliability. Mileage of 200,000 trouble-free miles is pretty common this engine. But still, there were some problems that 1MZ Toyota owners faced quite often.
Engines with high mileage typically consume an impressive amount of oil. And the condition of motor oil is critical for the 1MZ-FE, because it is prone to oil gelling (engine sludge issue), especially inside the intake manifolds. It is important to use good quality oil and do the required maintenance in time. The early MZ engines had poor knock control. The reliability of the knock sensor is low. Bad sensor causes a power reduction and rough acceleration. Toyota fixed that problem on the 3MZ-FE engine by installing a new flat-type knock sensor.
VVT-i components are a headache also. It leaks with oil or fails, causing shaking operation and drop of power. The engine with failed VVT actuator sounds like a diesel.
It is worth mentioning that the engine has an aluminum block, which is not rebuildable. If it is damaged, you need a new engine block or an entire replacement engine.