Under achiever

We exchanged our SEAT Ibiza 1.9 diesel, which had given us trouble free service achieving and sometimes exceeding the mileage figures quoted by the manufacturer, we decided to buy the new Seat Altea 1.6 ECOmotive, which gave us easier access, £35 annual tax and low emissions thinking we were "doing our bit for the planet" and the prospect of better fuel economy. The ride is smooth and noise levels possibly half of the Ibiza and it has all those extras that comes with the SE model. The in car computer read out matches the consumption figures calculated by refilling the tank The consumption is 46mpg (figures quoted are from 54 to 68 mpg) and is the same on a trip down the dual carriageway or around the local shops. We reported this to the dealer who basically said forget the brochure figures, they are a "myth" and we should be more than satisfied and cars never achieve these figures (our last 4 diesel cars have). My concerns are not just that extra fuel is costing us a fortune but what effect is all this extra fuel having on the diesel particulate filter and the catalytic converter is it shortening their life span? And how can the car still be in the low emissions tax bracket? How low do consumption figures have to be before you have a case of false description under the Trades Descriptions Act 1979? We are both in our 60ies and always drive for consumption not speed. Any suggestions as to our next move would be appreciated.

Asked on 10 July 2010 by SB, Newton Abbot,

Answered by Honest John
Yours is not the first report I have received of poor real life economy
from the VAG 1.6 diesel. The reason is that the particulate filter is designed to collect particles on start up, then use extra fuel to burn them off later in the car’s journey. If all you do are short runs, then extra fuel will continually be used for this and fuel economy will be poor. I averaged 55mpg over 8,000 miles in a Focus 1.6 ECOnetic with a DPF, so economy is feasible with some eco diesels. But, as I keep pointing out, if you do less than 15,000 miles a year and you don’t do regular long runs, you should not buy a diesel with a particulate filter. You should buy petrol instead.
Dear Honest John,

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