Volkswagen EA898 (4.1/4.2 TDI)

The Volkswagen Group's V8 diesel, fitted to the largest Audis and the Touareg — twin-turbocharged, common-rail, and built for torque rather than revs.

It repeats the group's V-engine timing layout at the rear of the block, so the chain job is an engine-out one on a very heavy engine, and the same rule applies: an age-related rattle is the warning, and it precedes any stored code.

Beyond that, the recurring themes are the ones any large modern diesel brings — EGR coolers, swirl flaps, injector wear and turbocharger oil supply — but the packaging makes each of them a substantially bigger job than on the four-cylinder engines. Access, not diagnosis, is usually what determines the repair decision here, which is worth saying to an owner before work starts rather than after.