Toyota 1ZZ-FE (ZZ family, 1.4–1.8)

The 1.8-litre engine that replaced Toyota's cast-iron 4A and 7A units with a die-cast aluminium block and thin press-fit iron liners, chain-driven rather than belt-driven — one of the highest-volume engines Toyota has built, and the Corolla's powerplant for a decade.

Oil consumption on the earlier examples is the fault that defines it, and the mechanism is specific: the original piston-ring design allowed the oil control ring to clog with combustion deposits, after which the engine burns oil at a rate that surprises owners who have never had to check it. Toyota revised the pistons and rings during production, so build date separates a car that will do this from one that will not more reliably than mileage does.

The practical consequence is the same as on the 2AZ and worth stating twice: an engine that consumes oil silently will eventually run low enough to damage itself, and the level is the first thing to establish on any running complaint. The thin liners also make this engine a poor candidate for a rebore, which shapes the repair decision when one has been run dry.