Nissan MR20

Nissan's 2.0-litre four, developed with Renault and fitted to the Qashqai, X-Trail and Sentra — the volume petrol engine of Nissan's crossovers for over a decade, in port-injected MR20DE and direct-injected MR20DD forms.

The engine's reputation is inseparable from the gearbox behind it, and that is the single most useful thing to know: most of these cars use a Jatco CVT, and a very large share of complaints that arrive described as engine problems — hesitation, flaring, loss of drive, a rising note under load — are transmission behaviour. Establish whether the complaint follows engine speed or road speed before opening anything.

The engine's own recurring items are the timing chain and its tensioner at high mileage, and on the direct-injected DD versions the usual intake-valve carbon. Both announce themselves conventionally: a rattle on start-up for the first, a rough cold idle and misfire codes for the second.