Diesel cars are more than three times as likely to breakdown than their petrol counterparts and are more expensive to fix when they do, according to new data.
Analysis of 30,000 faults on three to eight-year-old cars across a 12-month period by car ownership and maintenance firm, MotorEasy found that the average engine repair bill for a diesel was £517, compared with £433 for a petrol model, a difference of 20 per cent.
With engine faults in particular being far more prevalent in diesels than petrol cars, the biggest repair cost amounted to £4,030.80.
Diesel cars are less reliable than petrol for more than 71 per cent of manufacturers, with Alfa Romeo oil-burners faring the worst against their petrol counterparts and experiencing a fault almost four times as often.
Least reliable diesels
Vehicle manufacturer Average diesel failure rate Alfa Romeo 47% Land Rover 41% Mitsubishi 36% Saab 33% Mazda 33% Kia 29% Mercedes 27% Vauxhall 26% Mini 26% Audi 26%
The study suggests the most reliable diesel cars are made by Skoda, with a failure rate of just nine per cent.
Alfa Romeo, Land Rover, Kia and Mazda diesels have the highest average diesel engine repair cost versus petrol.
Only seven of 25 car makers analysed showed fewer breakdowns for diesel models – petrol-powered BMWs experienced faults 60 per cent more often, while Audi, Skoda, MINI and Peugeot also bucked the trend.
Duncan McClure Fisher, founder of MotorEasy, said: “Diesels experience many more small problems than petrol cars.
“They are less reliable and, when a big item goes wrong, it costs a lot more to put right.”
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