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Is DPF technology improving in modern diesel cars?

A few days ago the BBC R4 ‘You & Yours’ programme had a feature on DPF problems. It said that the Salvation Army, which apparently runs 700 company cars, had stopped buying diesel models because of DPF and other problems. The programme claimed that it was not just short journeys that caused these problems and that even high mileage fleet cars suffered if they were driven carefully to conserve fuel.

Asked on 26 October 2013 by RC, via email

Answered by Honest John
DPFs are getting better and diesel engines better at preserving them. The first generation were a bit of a disaster. But driving at 1500rpm will make it difficult for the DPF to regenerate, and a succession of short runs from cold will block a DPF, as the Post Office is now finding after buying a new fleet of diesel vans with DPFs. They only work where the vans operate in country areas and are driven distances. Currently, one of the worst purchases you can make is a used diesel car or van 3 – 6 years old, because of DPF, DMF, EGR and turbo problems can easily cost you an extra £4000 - £5000.
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