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I've driven petrol cars all my life. But when researching makes and models for a "new used" purchase pretty much everything we looked at recommended a diesel engine.

But we're having sudden second thoughts about the diesel. We're not heavy drivers: there's a daily school run and 20-60 minute weekend drive most of the time. But we holiday in the UK about 3 times a year - visiting relatives mostly - which is 200-300 miles each time. At a guess we do maybe 7-8k per year.

Although we live in a city, it's very hilly. Our current 1.6 petrol struggles with the hills.

Considering this usage pattern, in terms of overall fuel efficiency and possible DPF problems, does a diesel make sense?

  • Not all diesels have dpf’s... so may depend on year of manufacture... – Solar Mike Jan 27 at 22:07
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It depends on the nature of the journeys as well as the length. DPFs don't like running cold (they soot up), so if you're only doing short journeys (<10 miles, or lots of stop-start), you need to take them for a good run every couple of weeks - the commonly quoted one is 15-20 minutes at motorway speeds. This allows the DPF to get up to full temperature and burn off the soot.

From an efficiency point of view, a Diesel is better once it's warm and cruising, a petrol is better for stop-start and cold running. Personally, as you live in a city, I'd buy a Diesel for the weekends and holidays, and walk (or use public transport) for the school run...

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Based on your total mileage and described usage pattern no a diesel (particularly one with a DPF) would be unsuitable. They are less efficient on shorter runs and in stop-start traffic and the DPF needs regular runs at motorway speeds to trigger regeneration cycles.

You don't mention what your existing car is but many old-school naturally aspirated 1.6l petrols were a bit underpowered for what they were being asked to move around. A modern small capacity petrol turbo will have much better driveability and a more usuable torque curve.

The key is to make sure the engine is sufficient for the job you're asking of it.

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