Peugeot DV5 (1.5 BlueHDi)

PSA's 1.5-litre common-rail diesel, replacing the long-running DV6 across Peugeot, Citroën, DS, Opel and Vauxhall — the current small BlueHDi engine.

It carries the same wet timing belt as the PureTech petrol, which is the most consequential thing to know about it: the belt runs in oil on a fixed interval, degrades if the specified oil is not used, and sheds material that can block the oil pump pickup. Belt failure therefore presents as oil starvation rather than as a timing complaint, and belt history is the first question on any example of unknown provenance.

The emissions stack — SCR with AdBlue, a particulate filter and cooled EGR — supplies the rest of its fault profile, with reductant quality and injector crystallisation being the modern replacements for the mechanical failures the DV6 showed. As always, a short-journey duty cycle is behind most of what these systems report.