Nissan QG18DE (QG family, 1.6 and 1.8)

Nissan's 1.8 four — in the Primera, Sentra, Almera and Bluebird Sylphy.

It replaced the GA family and is an all-aluminium, chain-driven design with variable timing on the intake — a modern engine where the GA was a simple one.

⚑ Its known problem is the timing chain, and specifically the tensioner and guides. The symptom is a rattle for a second or two on a cold start, worsening over months, and it is genuinely worth acting on: a chain that jumps on this engine is an interference failure.

Carbon on the intake and throttle body is the other recurring item and produces a hunting idle and a hesitant pull-away, particularly on cars used for short journeys. It responds to cleaning rather than to parts.

Ignition coils fail one at a time and give a misfire under load before they give one at idle, which is the ordering worth knowing when a customer reports a fault that only appears on a hill.

The QG16DE and QG15DE are the same design in smaller sizes. The QR family that followed is a separate engine with its own page here.