Should I buy a diesel car?

It’s often the first question you ask yourself when buying a car: should I buy a diesel or a petrol car? The answer is a little more complicated than it used to be, but essentially it just depends on what you’re going to use your car for.

If you’re thinking about buying a new car and you’re wondering what your options might be, you can check out our blog ‘Is it better to lease or finance a car in the UK?’

We’re currently going through a pretty big shift in attitudes towards cars and the kind of cars people are using. With all sorts of hybrid and electric options becoming more and more available, it’s a good time to be wondering if you should be buying a diesel car. Luckily for you, we’ve put together this handy blog to help you to decide.

What happened to diesel cars?

For many years, the UK government actively encouraged drivers to buy diesel cars. They’re more fuel efficient than petrol cars, and produce less CO2, so they used to qualify as low-emission vehicles. This meant that you would pay practically zero car tax on a diesel car in the old days. Things have changed in recent years, however.

In 2015 the world was faced with a bit of a scandal when VW were found to have been fluffing their emissions tests on some diesel cars. This was the start of a whole load of drama around diesel cars, and people were particularly worried about how much they produce potentially harmful nitrous oxides. It’s actually generally agreed now that these worries were a bit inflated, as modern diesel cars are fitted with something called a DPF (Diesel Particulate Filter). This basically catches the harmful nitrous oxides from being released by the car and stops the exhaust from firing out the black smoke you might associate with an old diesel car.

People were essentially a bit scared by the scandal, and more and more people are wondering if it’s worth buying a diesel car anymore. In 2012, diesel cars outsold petrol cars. In 2021, just 135,773 diesels were registered, compared with 762,103 petrol cars. Sales are still dropping, with hybrid and electric cars already outstripping diesel purchases.

Pros and cons of diesel cars

So is it actually worth buying a diesel car? Well, it really does depend on what you need it for, so we’ve put together a few pros and cons for you to think about before you decide if you should buy a diesel car:

Pros of diesel cars

• Fuel efficiency - Diesel cars are more efficient than petrol cars, meaning you’ll get through your fuel slower, and probably save yourself some money. We say probably because fuel prices are up and down so much these days that it really is hard to say.
• Great on long journeys - The fuel efficiency of diesel cars make them great for consistent long-distance driving. You’ll have to stop less to fill up your tank, and a nice long journey will allow your DPF to work as efficiently as possible. They tend to need a nice hot exhaust to really burn off all the potential pollutants, so long journeys on motorways make sure they get hot enough.
• Lower CO2 emissions - This fact hasn’t actually changed, as worried as everyone has got in recent years. Diesel cars do still produce less carbon dioxide emissions than petrol cars, making them a bit more environmentally friendly.
• They’re getting cleaner - If you buy a new diesel car in the UK today, you’ll be buying a ‘Euro 6’ diesel, cars with the cleanest diesel engines ever produced. These engines add a special chemical (“AdBlue“) into the exhaust system that neutralises practically all harmful emissions. They of course also all have DPFs to catch any of that classic diesel smoke.
  

If you want to learn a bit more about running a diesel car, you can check out our blog ‘Can you put diesel in a petrol car?’

Cons of diesel cars

• High taxes - For cars registered since April 2017, road tax rules have changed. The costs are still grouped by emission levels, but they’re far stricter than they used to be, with diesel cars now sitting in a higher tax band than the equivalent petrol cars.
• Clean air charges - London now charges £12.50 per day to diesel car drivers driving within their clean air zone. A number of UK cities are planning to follow suit over the next couple of years, so inner-city driving is going to get expensive quickly.
• Fuel is more expensive - We all know diesel costs more than petrol litre for litre. This wasn’t an issue in the old days, because the fuel efficiency of diesel cars would still have saved you money. With fuel prices going up so much recently, it’s starting to be very expensive to run a diesel car.
• Doesn’t suit short journeys - Diesel cars aren’t just suited to long journeys, they practically require it. DPFs need to be nice and hot to work properly, so if you’re only driving short distances at low speeds, for example in urban areas, you could end up with a seriously clogged DPF. Diesel cars need a good long motorway journey regularly to keep them running smoothly.

Should I buy a diesel or petrol car?

If you’re trying to decide between buying a diesel or a petrol car, it’s a good time to consider how you drive and what you use your car for. If you’re driving short distances around urban areas it may be that a diesel car is going to be increasingly inconvenient for you. But, if you’re doing a lot of long distance driving, you might find that a diesel car is exactly what you need.

In either case, taxes and charges on both petrol and diesel cars are predicted to keep on increasing. The UK government has also already said that producing new petrol and diesel cars will be banned from 2030. There are some big changes coming to the car industry, so it’s a good idea to keep an eye on things as they shift.

If you want to learn a bit more about road tax, you can check out our blog ‘How long can you drive without road tax?’

A few final tips…

If you’re still wondering if you should buy a diesel car or not, here’s a last few things to consider:

• If you buy a car that was registered before April 2017, it may still be included in the old car tax rules, so an old diesel car might cost you less in taxes. It’ll probably still cost you more to drive in cities though.
• If you’re thinking of getting a diesel car as a company car because you’re going to be driving long distances, it’s worth pointing out that the government has also raised taxes on company cars, depending on your emission rates.

Urban Jungle is not a financial advisor and information in this article should not be taken as advice or recommendation.