The old wisdom was that diesel engines lasted forever, cost less to run and were simple to maintain, but 21st Century engine tech has turned these arguments on their head.
Take maintenance, for example. It’s true that diesel engines don’t need spark plugs, HT leads and coils. But they do need turbochargers to match the power of gas motors, dual-mass flywheels to smooth gearchanges, DPFs (diesel particulate filters) to cut emissions, glow plugs and expensive high-pressure fuel injectors.
And don’t pay too much heed to old stories about diesel engine longevity, either. Old gas engines didn’t last as long as old diesels, but increasing diesel complexity and better-quality gas motors could be levelling the playing field.
Remember too that most car maintenance costs are unconnected with the power unit.
Diesel engines were once the good guys in the war on emissions, but now the authorities have woken up to their highly toxic particulate emissions, the whole future of diesel for mass-market transport looks less certain.
The driving experience is very different too. Diesels deliver lots of mid-range torque for effortless pulling power and if you then step into a regular gas car you’re going to find it pretty gutless until you adapt your driving technique.
But gas cars respond well to revs, whereas diesels just run out of puff.
You’ll still get fuel savings from a carefully-driven diesel, but when you factor in purchase cost, maintenance and complexity, the equation gets more complicated. Maybe gas isn’t done yet!