Peugeot DW12

PSA's 2.2 HDi — 85 × 96 mm, DOHC, sixteen valves, from 100 PS to 204 in the DW12 C. One of the most widely borrowed diesels ever built, and the reason a fault found on a Peugeot 407 is worth reading on a Land Rover: beyond PSA it went into the Freelander 2, Discovery Sport and Evoque, the Jaguar XF, Ford's Mondeo and Transit, Fiat's vans, the Mitsubishi Outlander, and Tata's Safari and Hexa. Mahindra re-engineered it as the mHawk for the Scorpio and XUV500.

It is a genuinely durable engine and its reputation is earned — with fuel filters changed on time it will pass half a million kilometres. That is worth saying because it changes what a fault means: a DW12 running badly is much more often its fuel or emissions equipment than the engine.

What actually fails is the high-pressure fuel pump, which leaks, and the EGR valve, which clogs. Both present as poor running and neither is a bottom-end problem. Take a rough-running DW12 to the fuel system first.