What’s wrong with the Toyota 2.4 (2AZ-FE) one-off engine?

Engine weaknesses

The main problem is motors Toyota 2.4 2AZ is the same as the 1AZ power units – weak thread in the block for attaching the head. It leads to depressurization of the joint, which is accompanied by:

  • coolant leaks from under the gasket;
  • probable engine overheating;
  • violation of the adjacent plane of the head.
The oil pump is located in the crankcase and is driven by an additional chain.

When starting power plant from a cold state, noisy operation of the VVT-I system is observed, errors occur in the valve timing and in the VVT-I system. This problem is treated by replacing the intake camshaft sprocket with a modified version.

Periodically, noisy operation of the cooling system pump is noted, which is accompanied by the formation of a leak. To eliminate such a defect, it is recommended to change the pump every forty thousand kilometers.

The plastic intake manifold may produce extraneous noise when starting the engine from a cold state or when accelerating sharply. Quite often, errors occur in the VVT-I system due to clogging of the VVT-i valve filter.

There is an increased consumption of engine oil after the power unit has traveled one hundred thousand kilometers. On average, oil is burned from 200 to 300 ml per 1000 km.

A little history

The 2AZ FE debuted, along with other powertrains in the AZ family, in 2000. At this time, internal combustion engines with low fuel consumption and high environmental parameters became in demand in the global engine building market. But at the same time that the car was economical and environmentally friendly, the owners wanted to have a car with a powerful, reliable engine, which is equipped with the latest technical innovations. The design of the engine in question met all these parameters. The 2AZ replaced the technically and morally outdated 2.2-liter engine of the S series. Its production began simultaneously in three countries: Japan, the USA and China.

Refinement of internal combustion engines during production

Over 19 years of production, the engine was modified several times and the design was slightly changed. First of all, this concerns environmental equipment. The fact is that engines with an exhaust gas recirculation system were produced for the Japanese market. For markets of other countries, the EGR system was not installed on cars.

After 2006, the engine received new, more powerful bolts for securing the cylinder head. Previous bolts with 24 mm threads could not withstand the load. Sooner or later, they failed, which led to antifreeze leakage and all the ensuing consequences. New, more powerful 30 mm bolts solved this problem and eliminated the annoying problem for everyone.

Modernization in 2008 contributed to an increase in the compression ratio to 9.8:1, instead of the previous 9.6:1, and an increase in power to 170 hp.


2AZ-FE has insufficient maintainability due to the disposable cylinder block. Despite the impossibility of a major overhaul by definition, in practice there are cases of attempts to restore a block by boring and re-sleeving it. At the forum of owners of such motors, the statement of ARTEMenige from Novosibirsk deserves attention: “… yes, normal engines. During repairs, you can either bore or sleeve it. And after repair they run for 300,000 thousand without problems, if they are used correctly and filled with oil, and not counterfeit…”.

The most interesting thing is that neither this car enthusiast nor others give specific examples of major repairs of the cylinder block. Apparently due to the fact that the manufacturer does not produce liners and pistons of repair sizes. Moreover, if the piston rings are stuck, they are replaced under warranty, but assembled with the cylinder block and pistons.

The cylinder head is less problematic in this regard, although until 2006 it was considered almost the most vulnerable engine component due to the failure of the threads of the mounting bolts. Two options for solving the problem were proposed – installing studs with extended threads into the block or purchasing a repair kit of threaded bushings (screws) for mounting bolts.

All other components and mechanisms of the unit are repairable. The main type of restoration is the replacement of faulty parts with serviceable ones.

There are no problems with purchasing spare parts, but you must immediately be prepared for their high price and the possibility of purchasing counterfeit products.

Considering the high cost of spare parts and repair work itself, it is worth considering the option of purchasing a contract engine. The cost of such a unit depends on its configuration, year of manufacture and mileage. In digital value it ranges from 90,000 to 150,000 rubles.

Question answer

What happens if you remove the balance shafts?

Increased vibration of the engine and the vehicle as a whole. Ultimately, such a malfunction can lead to engine destruction.

Is it possible to clean the VVT-i clutch?

No. The VVT-i coupling is not dismountable and cannot be repaired – only replaced. But its filter and valve are easily cleaned with a special flushing liquid.

How to resolve error p072?

The error indicates an enriched working mixture. To bring its parameters back to normal, checking, cleaning or replacing the injector, fuel pump, air intake valve, air flow sensor, air filter, spark plug will help.

What is the tightening torque for the cylinder head? Tightening is carried out in two stages. On the first – with a force of 70 Nm, on the second, an additional rotation of 90 degrees is carried out.


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