Helpdesk

THIS WEEK:Distributors need to clean up filter issue on diesels

From CL, Waterford: I purchased a new Mazda 6 diesel in 2010. I was doing a lot of long distance motorway driving but over the past six months have tended to do more short city journeys. Last November the DPF (diesel particle filter) warning light came on, and I had to bring it to a main dealer to have it "regenerated". Mazda Ireland told me it is not covered by warranty and could give me no assurance it would not happen again unless I was doing regular long distance driving. So I'm looking for a more suitable car. However, I am conscious of the AA's advice: "If you're buying a new car and plan to use it mainly for town-based, stop/start driving it would be wise to avoid a diesel car fitted with a Diesel Particulate Filter (DPF) because of the possible hassle of incomplete 'DPF regeneration'." But the sales advice is that a petrol car will lose its value very quickly as the future is diesel.

This is a growing problem for diesel owners and a real issue with Ireland's diesel fixation, which has meant that several car firms have stopped offering petrol versions of their models.

Most modern diesels are fitted with DPFs as part of efforts to reduce emissions and thereby benefit in terms of tax. The DPFs absorb particulate emissions created during the start-up phase of an engine from cold. These particulates are burned off during the "regeneration cycle". But if the car is only used for short trips the process hasn't time to complete. So the light comes on and you have to go to the dealers to get it "regenerated". That shouldn't take more than 30 minutes. But if the DPF needs replacing that could cost €1,500 to €3,000 depending on the brand. The problem has become so common that there's anecdotal evidence of DPFs being stolen from cars.

Buyers who only do short hops should really consider if a petrol engine might be better for their needs to avoid these potentially high costs. It's true, however, that with Ireland's diesel fixation, resale values on petrols are poor.

It's a catch-22 for buyers. I think you would really be better in a petrol car but your choice may be limited and resale values will suffer. Buyers - and dealers - need to take a more considered view of individual customer needs.

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