Is a used diesel a smart buy in 2018?

JACK COOPER
It's hard to escape the fact that diesel is "so last decade" these days. Once hailed as the future of consumer motoring, it has fallen from grace in the most spectacular fashion in the last few years - thanks mainly to Volkswagen's 'dieselgate', and a greater understanding of the environmental impacts.

To buy a brand new diesel car today isn't considered a particularly smart move, but that doesn't change the fact that hundreds of thousands of diesel cars still flood the used car market, and some of them are temptingly cheap. But should you buy one if you're looking for a set of wheels on a budget?

While the agenda set in this day and age is to steer away from the oil burners, there are still plenty of reasons why a diesel car looks attractive to the everyday driver who works on a budget. For example, diesel cars are inherently more fuel-efficient than petrol equivalents, since diesel fuel is more energy dense than gasoline. On the motorway especially, diesels can pull an easy 20MPG advantage over petrols, while maintaining the same performance.

You'd be stretched to get a petrol Astra to return 74MPG | Image: businesscar.co.uk

Diesel cars also offer performance characteristics that suit laid-back, real-world driving. Engines are torquey, and more often than not pull from very low revs, which means you don't have to work to gearbox to make the car move. The torque surge can be addictive to some more spirited drivers, too.

So far, so good. Sounds like a fairly conclusive "have your cake and eat it" kind of situation, doesn't it? Good performance, good economy. However, now let's explore what may turn you away from buying used diesels.

For that, we have to come back to the overall negative opinion of diesel cars in the present day. For better or for worse, governments across the globe are feeling more and more pressure as the days go by, to impose sanctions on diesel cars that try and persuade motorists away from them. In London, for example, the Ultra Low Emission zone will come into force in 2019/20, where any diesel registered before September 2015 will be charged an extra £12.50 on top of the existing £11.50 congestion charge. This strict rule only applies to petrol cars produced before 2006, which will be 14 years old by that point.

Paris, Madrid, Athens and Mexico City have all announced plans to remove diesel cars from their roads entirely by 2025. That may not matter to the vast majority of motorists who drive outside these cities, but consider how long it will take more localised councils in your area to follow suit; probably not that long. 

Photo: PA

Used diesels also have a greater chance for something to go wrong with them. According to analysis from MotorEasy, diesel cars that are three to eight years old are three times more likely to break down than their petrol counterparts, and will cost 20% more to repair. Modern turbo diesels are more complicated in design, and experience greater stress than petrols, thanks to high compression.  Duncan McClure Fisher, founder of MotorEasy, was quoted saying: "If you're still considering a used diesel car, our advice is to avoid high-mileage examples." 

To sum it all up, diesels still have their appealing natures to drivers, but the war against them cannot be ignored. If you buy a used diesel today to use for the next five years or so, money you save on fuel and VED could be far outweighed by the potential repair bills and future government diesel penalties. Proceed with caution!