Do diesels still pay?

Used car buyers choosing diesels over petrol cars are unlikely to save money unless they cover over 10,000 miles a year.

That’s the verdict of valuation experts at Glass’s Guide. They say drivers not only pay more to buy a new diesel, but the difference grows on the used market – with fuel prices increasing demand.

Glass’s managing editor Adrian Rushmore said: “The average new family diesel costs £1,300 more than the average petrol model. But the gap increases to £1,900 (see table) at three years old.” 

Yet demand for diesels isn’t just driven by fuel costs; it’s also down to the cars’ driveability. “Modern diesels have more torque and run as smoothly as petrols,” added Rushmore. Glass’s calculated the 10,000-mile tipping point after analysing thousands of car prices and factoring in fuel costs. 

Auto Express worked out that drivers buying a used petrol Vauxhall Zafira and driving 6,000 miles annually would save more than £1,000 over three years, after paying for more fuel. Rushmore said owners would still be in the black after shelling out more for road tax and selling the car, too.

The good news is that the difference isn’t likely to grow. Rushmore said: “Diesel sales overtook petrol last year, so prices shouldn’t rise.” And AA technical specialist Vanessa Guyll added: “There’s more to go wrong on modern diesels, and they’re more expensive to fix.”

How used prices compare:

Petrol vs Diesel model / Avg Price Diff

Ford Focus 1.8i vs 1.6 TDCi / £1,750

Audi A3 1.6 vs 1.9 TDIe / £1,800

BMW 320i vs 320d / £1,700

Peugeot 308 1.6 VTi vs 1.6 HDi / £1,700

Vauxhall Zafira 1.8i vs 1.7 CDTI / £1,900

Source: Glass's guide

Reader case study

Reader David Watters made the switch from diesel to petrol after his annual mileage dropped from 25,000 to 5,000 miles. David, from Edinburgh, traded in his Skoda Fabia TDI for a petrol Toyota Yaris, and told us: “I only do short journeys now, and as the diesel was barely warming up the economy wasn’t even any better than a petrol car’s.”