What Car? Q&A - Are VW diesel engines changing?

Q: I've heard from various sources that VW are about to ditch their 'Pumpe Duse' engines, in favour of the industry norm, the common-rail diesel engine. Is this true, and, if so, when is the change likely to take place?
Francis McAvennie

A: You've heard correctly - Volkswagen recently announced the ageing PD (Pumpe Duse) engines will shortly be replaced by a more-efficient common-rail unit.

Pumpe Duse roughly translates as 'unit injector'. This system allowed very high injection pressures, and, when the technology was new, it meant more power and lower fuel consumption.

However, Volkswagen has accepted its key rivals have bettered its PD engines for efficiency and refinement.

PD engines are rougher and less economical than those whose diesel is delivered into the cylinders via a single fuel pipe (hence 'common rail').

The first car to get the new engine will be the Golf-based Tiguan 4x4, set for launch in early 2008.