All of you who have the inclination, Go to a dealer, any dealer, and not one of them will ask what you want the car for. One of the other points is that "DPF filters" "will not last the life of the engine." The EU are making it harder and harder to run an engine efficiently by reducing emissions willy-nilly. While there was a case for catalytic converters, current technology is asking for emissions levels to be reduced by adding layers of complexity, 3 way cats, dpf's stop start, twin dsg twin clutch gearboxes. Get any 2 of these failing at 3 years and the car will be uneconomic to repair, and see the warranty exclusions for dual mass fltwheels, dual clutches etc etc. Next car for me... mid sized medium engined petrol when mine is out of warranty and the right vehicle presents itself, but at a guess something with a 5-7 year warranty, ordinary gearbox and the least electrical bits possible.

Particle filter (PF) Particles have a diameter of around 0.09 microns and consist mainly of carbon and hydrocarbons. The PF traps these particles and periodically burns them off. Particles burn naturally at approximately 550 °C, but the normal temperature of exhaust gases leaving the manifold is only 150 °C.

The particle filter system overcomes this problem in a number of ways : post-injection during the expansion phase, resulting in post-combustion in the cylinder and a 200 to 250 °C increase in exhaust gas temperature (i.e. to between 350 and 400 °C) ; additional post-combustion by means of an oxidising catalyst located upstream of the filter.

The catalyst acts on any unburned hydrocarbons resulting from the post-injection and raises the temperature by a further 100 °C (to between 450 and 500 °C) ; use of Eolys, a cerine-based additive that reduces the particle combustion temperature to 450 °C.

The particle filter system consists of the following : a housing containing the pre-catalyst and filter. The filter is a porous block of silicon carbide that traps all particles in the exhaust gases. Sensors monitor clogging pressure across the filter and the gas temperatures at the inlet and outlet of the system ; a software programme in the engine control unit that controls regeneration of the filter by post-injection every 400 to 500 km depending on the clogging pressure across the filter.

The software also provides diagnostic information on the system. During regeneration, the inlet air is no longer cooled by passing through the air-air intercooler but is instead heated to raise the temperature of the mixture in the combustion chamber with a consequent increase in the temperature of the exhaust gases ; a fuel additive system consisting of a probe tube, a system to inject Eolys into the main fuel tank and a dedicated electronic controller.

The Eolys is stored in a tank adjacent to the main fuel tank and injected in proportion to the volume of fuel added during refuelling. For example, when filling up with 60 litres of fuel, the system will inject 37.5 ml of solution containing 1.9 g of cerine. The Eolys tank has a capacity of 5 litres, sufficient for 80,000 km. The filter is cleaned and the Eolys tank refilled during dealer servicing every 80,000 km.

Edited by Avant on 22/10/2011 at 20:30

I just replaced my 8-year old, Euro III Focus TDCi with a 7-year old, Euro III SEAT Leon 1.9TDI, just to avoid the DPF issues.

I'm hoping the VW TDI will be as reliable as 659FBE claims!