From there the path leads to the turbo. A fine gauze filter sits in the banjo bolt of the turbo's oil feed pipe, and the soot blocks it. Measured on such a car, the oil pressure at the turbo at idle was 0.8 bar, while the specified minimum is 2.3 bar; after the gauze was taken out it became 3.4 bar. With that much less oil the bearing of the turbo fails, and that typically happens above 130 000 kilometres.

The early signs are the smell of diesel in the cabin and black, oily deposits around the injectors on the engine cover.

The repair is not just the turbo, and that is the most important part of it. The oil feed pipe and its banjo bolts, the sump, the oil pick-up strainer, the oil filter housing and the oil cooler, the intercooler, the particulate filter with the exhaust and the vacuum pump of the brake system all have to be cleaned or replaced, and all the injector sleeves, seals and copper washers have to be replaced. If any of these is left out, the new turbo goes the same way.

Above 200,000 km the bearings can drone and the dual-mass flywheel can knock. The oil level is worth watching, because leaks are common and the gearbox tolerates a dropping level badly.

At high mileage the synchros on the first two gears wear out, and then the shift grates. The gearbox comes with a dual-mass flywheel, which is not the most durable part either.

The leak is the more dangerous one: any drop in the oil level wears the shafts and the gear rims, and that wear cannot be undone. Most versions come with a dual-mass flywheel, which is not the most durable part either.