Ask Honest John

Most recently answered dpf questions
I was interested to read your recent comments about certain vehicle models appearing to be DPF trouble-free. Is this because they have markedly different systems for regeneration of the filter, or some...
I notice you were yet to be made aware of any DPF issues with Mazda Skyactiv diesels so I thought you might like see the attached which comes from the May 2013 issue of Diesel Car. Are you seeing any evidence...
We are looking at a used motorhome. Most of what we are looking at seem to be based on a Fiat Ducato diesel chassis. In general, are there any older motorhomes that could suffer from Dual Mass Flywheel...
I have recently moved from France to Guernsey and from reading your Daily Telegraph column am concerned about potential DPF problems due to low usage. However I am not sure if DPFs were fitted back in...
It is now time to change from my nine-year old BMW 525 diesel. I am retired and do about 4000 miles per year. I do lots of short journeys of around seven miles, with very occasional longer trips. The dealer...
I have noticed while travelling between 50-70 mph that the engine of my Mondeo 1.6 TDCI seems to hesitate or cut-out momentarily, and then cut back in immediately without any dashboard indication. What...
My postman tells me that Royal Mail recently took delivery of new Fiat vans fitted with diesel particulate filters. Now postal workers on suburban stop-start 'walks' are sitting revving the engines to...
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...
I had a very interesting chat with a service manager at BMW Battersea whilst collecting my car. I have a 12-month-old new model X3 3.0-litre diesel. I do a low mileage for a diesel (about 9000 miles a...
A friend is purchasing a Porsche Cayenne diesel with a stop-start fuel saving cut-out facility. Firstly, does this rapidly destroy a battery (with all the re-starts)? Secondly, as a diesel with a DPF,...