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Should I buy a diesel car? Find out the answer that’s RIGHT for you

There’s been a lot of bad press about diesel over the past few years, sparked by the VW ‘Dieselgate’ scandal in 2015 – but if you cover a high mileage or usually drive on the motorway, diesel still makes sense. Here we’ll get to the truths and misconceptions of diesels and help you answer the question: ‘Should I buy a diesel?’

It wasn’t all that long ago that diesel cars were all the rage, and it’s easy to explain why. With the world focused on global warming and the environment, and Carbon Dioxide (CO2) accepted as a major cause, governments wanted to encourage people into low-CO2 cars – and that’s exactly what diesel cars are. Compared to an equivalent petrol engine, the diesel engine will emit less CO2.

As a result, here in the UK, the Government gave incentives for us to choose low-CO2 cars – linking road tax and company car tax to CO2 emissions, for example – while it wasn’t unknown for councils to set the price of parking permits using this set measure. As a result, the sales of diesel cars boomed.

However, that pro-diesel tide turned, partly because of what one maker was found out to be doing in America, and partly because it’s not all good news about the emissions from diesel engines.

Trouble is, while diesel engines produce relatively low levels of CO2 – which is good for the long-term health of the planet – they also produce relatively high levels of Nitrogen oxides (NOx), which is linked to health problems in humans, especially in traffic-dense cities.

Watch our video to decide if diesel or petrol is right for you or answer a few questions in our Fuel Chooser.

Demonisation – the stigma of diesel

The VW ‘Dieselgate’ scandal is more than likely the reason why you’re wondering if diesel is right for you. Back in 2015 it emerged that some car makers had been cheating the official fuel-economy tests, meaning that their cars’ emissions and fuel economy figures were far worse in everyday use than they were in lab conditions.

As a result of the scandal, a new test – the Worldwide Harmonised Light Vehicles Test Procedure – was introduced in September 2017. The intention is that this will produce figures for both diesel and petrol-powered cars that more accurately reflect everyday driving as well as removing any possibility of cheating the tests.

At the same time as this, air pollution has become a huge issue for governments both here and abroad, and much of the blame has been laid at the door of the relatively high level of nitrogen oxides (NOx) emitted by diesel vehicles. As a result, in a well-publicised move, some German cities have been given permission to ban older, dirtier diesel cars from parts of the cities, and it’s possible that UK cities could follow suit.

The inevitable end result is that people are worried about buying diesel cars, as they’re not sure what the future holds. However, it’s crucial to note that the problems outlined in the Dieselgate scandal – and the proposed bans in Germany – affect older diesel models. Thanks to exhaust treatments such as AdBlue and diesel particulate filters, modern diesel engines are fully compliant with the latest Euro6 emissions standards.

Rules – how upcoming changes affect diesels

Not only are people put off buying diesel cars because they’re worried about how diesel cars might be treated in the future, they already know that anti-diesel measures are coming in.

Some German cities intend to ban older diesel cars, while in London, the recently introduced T-charge means that drivers of pre-2006 diesels that do not meet Euro 4 emissions standards have to pay an extra £10 a day to enter the Congestion Charge zone – on top of the C-charge.

Beyond that, on 8 April 2019, London’s new Ultra-Low Emissions Zone comes into operation. Unlike the Congestion Charge, this operates 24 hours a day, seven days a week, and it will charge drivers of non-Euro 6 diesels (and non-Euro 4 petrol cars) £12.50 on top of any other charges to enter the zone. Once this is up and running, other cities are expected to do the same.

You can find out more information on tax bands by reading our road tax bands guide.

Costs – why diesel may still make financial sense for you

Regardless of all the anti-diesel feeling, it’s quite possible that a diesel car is the best choice for you.

That’s despite the fact that diesel cars tend to cost more to buy than their petrol equivalents and they can be a little dearer to service, while the fuel also costs more. However, diesel cars are more economical than equivalent petrol models, and if you do enough miles you’ll eventually save enough money in fuel bills to recoup that extra initial cost.

This is called the break-even point, but it’s very important you do the sums carefully to make sure you don’t end up choosing the wrong engine for your motoring life. The point at which you recoup the diesel premium can vary wildly depending on the car’s price and economy. Here we’ve calculated how many miles you’ll have to travel to recoup the cost of buying a diesel.

Our examples in the table below take account of the fact that carwow savings on diesels are often better than on their petrol counterparts, and also include our own real-world fuel economy figures rather than using the overly optimistic figures from the official tests, because this matters a lot when doing the calculations. Confusing, we know! Note that we’ve picked diesel and petrol engines with similar performance.

How far will I have to drive to recoup the costs of buying a diesel?
Car Petrol Diesel Total miles to break even
Volkswagen Golf 1.0 TSI 110 5dr SE petrol 1.6 TDI 115 5dr SE 89,200
Skoda Kodiaq 1.4 TSI 150 DSG SE 2.0 TDI 150 DSG SE 45,400
Ford Fiesta 1.0 Ecoboost Nav Zetec 5dr 1.5 TDCi Nav Zetec 5dr You’ll never break even*
Peugeot 3008 1.2 Puretech Allure 1.6 BlueHDI 120 Allure 44,000
Nissan Qashqai 1.2 DiG-T N-Connecta 1.5 dCi N-Connecta 12,100
Mercedes C-Class C200 Sport C220d Sport 53,800
BMW 1 Series 118i Sport 5dr 118d Sport 5d 6100
Honda Civic 1.0 vtec turbo SR 1.6 i-DTEC SR 25,700
Audi A5 Sportback 2.0 TFSI S Tronic 2.0 TDI Ultra S Tronic 48,600
Vauxhall Mokka X 1.4T ecoTec Active 1.6 CDTi 136 Activ 32,300
*The Fiesta’s diesel engine costs more than the petrol and is less economical – so you’ll never break even

If you’re a high-mileage private buyer that fancies a Skoda Kodiaq in SE trim, and are torn between the 1.4 TSI 150 petrol or 2.0 TDI 150, you’ll be quids in once the odometer of the diesel version passes 45,400 miles. So if you do 10,000 miles per year you’ll need to keep the diesel Kodiaq for four years to recoup the extra purchase cost.

Likewise, if you want a Volkswagen Golf in SE trim, and can’t decide between a 1.0 TSI or a 1.6 TDI, perhaps the fact that you’ll need to do a whopping 89,200 miles in the diesel before you break even will nudge you in the direction of the petrol model. Unless you’re a really high mileage driver or plan on keeping the car for a very long time it’s not a great choice.

However, some diesel cars recoup their costs far more quickly. The Nissan Qashqai is a regular top-10 seller in the UK, and the break-even mileage between the equivalent 1.2 DIG-T petrol and 1.5 dCi is just 12,100 miles – an easy diesel win then. And the 1.5-litre diesel is actually nicer to drive!

Same goes for the BMW 1 Series. You’ll need to do just 6100 miles to make up for the extra outlay on the diesel 118d over the petrol 118i.

Bear in mind you also need to factor in the cost of the AdBlue diesel additive, which minimises the harmful emissions. This costs around £15 for 10 litres, and you’ll use around a litre every 600 miles.

Check out how much you can save on all these cars by visiting carwow’s car chooser. Browse our most-popular models or choose a car based on its usage, the number of seats it has, fuel efficiency and performance.

You only have to travel 6,100 miles to break even in a 1 Series diesel (left), but 89,200 miles in a diesel Golf (right)

Driving – choose the right fuel for your needs

Choosing the right fuel for you isn’t just a case of doing a few calculations. You also need to take into account how different the engines feel from behind the wheel.

Diesels provide very strong pulling power at relatively low revs, which helps them feel relaxing to drive, because you don’t have to change down a gear so often to get decent acceleration.

As a result, they’re great for long journeys at higher speeds, so if you have a long commute or have to travel halfway up and down the country each day as part of your job, a diesel will suit you better. For the same reason, diesels are great if you plan on towing with your car or regularly carry lots of passengers.

In comparison, petrol engines typically have less pulling power, so need to be revved more to achieve the same performance. On the other hand, they tend to have much more power at high revs, and that’s great fun to exploit if you’re driving hard. Petrol engines are also generally smoother and quieter, and they tend to be best in, say, a small family car that spends the bulk of its life in heavy traffic. Petrol engines also emit less NOx in this situation.

Depreciation – how to safeguard against it

Depreciation has traditionally also tended to favour diesel cars, which have held their value better than petrols; however this trend is set to reverse as a result of all the negative press about diesels.

Andrew Mee, senior forecasting editor (UK) at Cap HPI, said: “The clean air debate could impact on consumer demand, but we do not expect any disruption to used car values. The current trend for diesel values to deflate slightly more than petrol values will continue, as the supply of used diesels will outweigh demand.

Conversely, used petrol and hybrid cars will be in more demand and this will support their values. The shift in the balance between petrol and diesel will be most felt in small cars; with larger cars and where drivers cover high mileages and/or need to carry many passengers or to tow, then diesel will continue to make sense.”

This will have a knock-on effect if you’re intending to buy your car using a Personal Contract Purchase (PCP) or Personal Contract Hire lease. In both of these instances, the car’s value at the end of the contract is used to work out how much you’ll pay each month, so if it’s worth less, you’ll have to shell out more each month – but you won’t have to worry about the value of your car shifting during the course of the agreement because it’s agreed up front.

Head to the carwow leasing deals page to see the most money you can save today – with everything from 0% finance deals to no deposit offers, scrappage scheme deals and immediate delivery offers.

Deals – how you can benefit from the situation

The sudden upsurge in the popularity of petrol models has caught manufacturers on the hop. They’ve been churning out diesel cars at some speed, and changing things around to place an emphasis on petrol is not the work of a moment. So dealers’ stock lists are packed with diesels.

Basically, if you’re willing to take a diesel car that’s already built, you can have your new car in a matter of days instead of months. There are fewer petrol cars in stock, so you’re more likely to face a lengthy wait – and the likelihood is that you won’t get as good a deal as on a diesel.


Alternatives – electric, hybrid and hydrogen

If you decide that diesel isn’t for you, there’s no law saying you have to go for a petrol car. In fact, there are plenty of other options, including electric, hydrogen and hybrid cars – and each will suit a particular type of motoring life.

Pure electric vehicles – including the Nissan Leaf, BMW i3 Electric and Volkswagen e-Golf – are superb in town, where they emit no fumes and are virtually silent. They’re also very relaxing and responsive to drive, and can be much cheaper to run than a petrol or diesel car – especially as they incur tax at very low rates.

On the downside, they’re expensive to buy and won’t go as far on a single charge as a petrol or diesel car will go on a tankful of fuel. Plus, when you need to recharge your car, you’ll need to be able to leave it for a fair chunk of time – and have access to somewhere to charge it in the first place.

Still, if your commute is short enough, or you can easily recharge the car at either end of your commute, an electric car is undeniably attractive.

Hybrids – such as the Mitsubishi Outlander PHEV, Toyota Prius Plug-in and Volkswagen Golf GTE – combine electric motors with a regular combustion engine, and have several benefits. For instance, you can refuel at any conventional fuel station and they have super-low tax rates for private and company drivers, while the conventional engine gives it a range of several hundred miles.

Like electric cars, hybrids work best in town, when you can take full advantage of the fuel-saving electric motor. However, on faster roads the electric motor is effectively redundant and the petrol engine has to do pretty much all the work, which means it’s shifting all the usual mechanicals plus the electrics, and quite possibly using more fuel to do so.

You can also pick something called a plug-in hybrid, which has a bigger battery that you can plug in to charge up and gives a longer range. However, the electric-only range is relatively short (typically no more than 20 or 30 miles), so a plug-in hybrid is most likely to suit you if you only travel short distances and have easy access to charging facilities.

Check out our lists of the best electric cars and best hybrid cars if you think these cars are right for you.

The other choice that you might be tempted by is a hydrogen car. At the moment, very few are available (including the Toyota Mirai and Hyundai ix35 Fuel Cell and they’re extremely expensive, but the attractions are that the cars only emit water and are very tax-friendly as a result. They also offer as much range from a tankful of fuel as a conventional petrol or diesel car.

On top of that, a hydrogen car is essentially an electric car, so it has all the same advantages on the road: it has no shortage of performance, is relaxing to drive and very quiet.

The big problem is that there are very few places in the UK – literally just a handful – where you can fill up a hydrogen car. And, that’s a shame, as it’s no harder or expensive to fill up than a petrol or diesel car.

For now, a hydrogen car will only suit a tiny number of people, but if you live near one of the few hydrogen filling stations, that could be you. For more information on hydrogen cars, read our detailed article on the subject.

Research – check prices to make the right choice

Head over to our car deals page to see carwow’s latest discounts or use our handy car chooser tool for more options. Get an idea of how much your next car could cost per month by using our PCP calculator.

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