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Should I choose petrol or diesel?

Hi guys,

My question has two parts. Firstly I am changing car and always drove a diesel but am wondering about improved economy of modern petrol engines, e.g. VW Jetta 1.4 TSI vs.  VW Jetta TDI. Maybe you can advise what criteria I should consider?

Also, as my mileage is difficult to predict, I am concerned that if I am not doing enough miles I will have problems with the particulate filter on a diesel. What do you think?

Peter Power

May 2011 Filed under: fuel economy and emissions

Expert answer

Hi Peter,

Diesel cars are now outselling petrol cars by 3 to 1 and of the petrol models that are selling, they are mainly small runabouts. The fact is that the majority of people are being drawn to the lowest possible road tax and in some cases, oddly, this means that they are actually spending more on the car then they really should have. There seems little sense to spend €2,000 - €3,000 more on a diesel car if you are saving €50 a year in road tax and your mileage is low, but that is the way it seems to be happening right now.

The problem with this is that buyers are missing out on on some really good petrol cars. Fiat and Volkswagen in particular have some smart new petrol engines. Take for example the Jetta, which you  mentioned: the new one is out now, but in the older model there was a 105hp 1.2-litre TSI petrol engine and most people baulked at this because they thought it would be too weedy for the car. The same is true of the 1.4-litre TSI, while both are more than capable of adequate performance. 

In terms of fuel economy, sure enough the diesel will usually trump the petrol, but this will only really start to make monetary sense when you do a lot of mileage. It you intend on high mileage, then you are probably better off sticking with the diesel car - Volkswagens are generally quite good at mega mileage, as are Skodas.

We've been getting quite a few queries about DPFs (diesel particulate filters) here in but Mazda appears to be the only brand showing up faults. The Passat though has not been without its troubles and, to be honest, I am not sure if I would be buying a used one with a lot of kilometres on the clock if big mileage is likely.

You mentioned the Jetta, well this one we found would be a top buy. It has just 14,000 miles on the clock, the right 2.0-litre diesel engine and is within your budget. This would be a good buy.

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