Diesel vs. Petrol - Demystifying the diesel problem

Diesel cars have always had their fans, but recently diesel has almost become a dirty word after reports about the amount of dangerous pollution they produce. So, what’s the truth, should you buy a diesel or a petrol engine car? Which is the best option for drivers?

The background

Not too long ago, diesels were said to be more environmentally friendly than petrol cars. There were even tax breaks to encourage more people to drive them.

But more recently, diesel car taxes have been hiked up and sales have fallen, because that view has changed and it’s now thought that petrol engines are actually the cleaner option.

Fuel image

Diesel vs petrol – the differences

Diesel engines are generally more efficient than petrol engines and should use 15 to 20 per cent less fuel than a petrol engine of the same size.

That means they should produce less of the greenhouse gas CO2 than petrol-powered cars, which is blamed for global warming.

But recently, attention has shifted to the other pollutants which can also be found in diesel exhaust fumes, which can cause serious health problems. Petrol engines tend not to produce as many of these other toxic ingredients.

How bad for the environment are diesel engines?

The good news is that, in general, both petrol and diesel engines are getting more environmentally friendly as stricter laws are introduced and manufacturers work out new ways to make their cars produce less pollution.

And it’s claimed that the cleanest new diesel engines can be less damaging than some petrol engines.

That said, most people agree that, in most cases, petrol cars are less harmful option to the environment.

Is Petrol or Diesel Cheaper to Drive?

It’s true that diesel cars can often do more miles-to-the gallon that petrol cars, but car tax is now often more expensive for diesels because the Government wants to encourage more people to use cleaner alternatives, including petrol, electric and hybrid cars.

That can eat into the cost savings that diesel cars can achieve by using less fuel. Diesel fuel is also more expensive than petrol.

Diesel cars tend to cost more to buy, and their falling popularity means they no longer hold their second-hand value as well as they used to.

But diesel motoring can still be cheaper for those who drive long distances every year, preferably on motorways, and keep their cars for many years.

The alternatives to diesel

The most effective way to keep motoring costs low is now to own a less-polluting car, whether that is petrol, diesel, hybrid or electric.

Cars that produce lower emissions cars can qualify for lower road tax and discounts on the London Congestion Charge, and they tend to use less fuel, so you save money at the petrol station too.

Do your research

If you are buying a new or second-hand car, you can check out its fuel consumption, CO2 emissions and tax band at the Government’s Vehicle Certificate Agency website.

Think about how many miles a year you drive, as well as the cost of fuel and tax, and carefully weigh up your options.

We wouldn’t write off the diesel option, but a lot now rides on how you use your car, so it will pay to do your research.