Opel Ecotec Z-family

Opel's small and mid-size petrol fours of the Astra H and J era, in 1.2 to 1.8 litre forms and known by their Z- and A-prefixed codes — the volume engines of the Astra, Corsa, Meriva and Zafira for two decades.

The recurring failure is the timing chain and its tensioner on the 1.6 and 1.8 Twinport versions, and it is more urgent than a chain complaint usually is: wear is often rapid, the noise is a rattle on start-up that owners describe as a diesel sound, and a jumped chain on this interference design ends the engine. On any Astra H or J with that noise, treat it as immediate.

The second theme is the camshaft position sensor and the phasing solenoids, which set timing-correlation codes that look identical to genuine chain wear — so the two need separating before parts are ordered. Thermostat housings, which are plastic and warp, are the other frequent finding.