Engine Overview and Common Failures
The weight of the 1AZ-FE engine according to the catalog is 131 kg. The engine number 1AZ-FE is located at the junction of the block with the gearbox. In engines of the first years of production, there were cases of cylinder head bolts failure due to the use of bolts with too short thread, which led to gasket damage and the appearance of emulsion in the expansion tank. In 2006, the manufacturer increased the length of the thread and the problem occurred less frequently.
Oil consumption after 150,000 km mileage is a characteristic feature of engines after 2006, probably due to the update of the piston rings with the use of thin oil control rings.
The timing chain of the AZ engine, a single-row bush-roller chain, is more reliable than modern plate chains, but often requires replacement closer to 200,000 km mileage, usually together with the camshaft adjuster.
This power unit does not tolerate low-quality fuel and quickly becomes dirty as a result. To find the cause of fluctuating RPM, it is worth starting with cleaning the throttle body, idle air control valve, and injectors.
Small breakdowns are also characteristic here, such as the limited lifespan of the water pump and the overrunning clutch of the generator. And since there are no hydraulic compensators, valve clearance adjustment is required every 100,000 km.