Should I buy a diesel or petrol car?

Choosing between the most common engines on the market, petrol and diesel, is an age-old problem. Perhaps you don’t give it much thought. But, when buying your next car, it can be helpful to understand how they differ so you can choose the option that suits you best. To make things more complex, the car world is dramatically changing with the rise of hybrid and all-electric motors and a soon-to-be ban on both petrol and diesel. In this guide, we’ll explain the upcoming ban and how it affects you. Next, we’ll tell you which came first, the pros and cons of both and which will last longer to help you make your mind up. 

What is the 2030 petrol and diesel ban? 

To help tackle our climate emergency, all petrol and diesel cars are set to be banned from sale in 2030. Designed to encourage manufacturers to go all-electric and reduce greenhouse gas emissions, the ban will hopefully give buyers more affordable electric alternatives. The sale of plug-in hybrid cars will also be banned by 2035. But don’t panic. This doesn’t mean you can’t buy them now. Nor does it mean you’ll have to ditch your petrol, diesel or hybrid car in 2035. It’s simply a ban on sales, so when you’re ready for a new vehicle, your only choice will be all electric.  

What came first diesel or petrol? 

It’s hard to pinpoint exact dates and it’s a close-run contest but petrol likely takes the title by just one year. Sources suggest that petrol was seen as a fuel in 1882 and diesel in 1883. However, they’re both by-products of the same scientific process so they were probably discovered at roughly the same time.  

Pros of diesel 

Good for long trips 

If you clock up lots of motorway miles, a diesel engine is ideal. At low engine revs diesels deliver more power than petrol engines and don’t need to work as hard. 

More fuel-efficient 

Most diesel cars have a better mpg than their petrol counterparts. This is because in the same amount of fuel, diesel has more energy. So, although diesel fuel is more expensive, you’ll have to fill up less often, which could make it better value in the long run. 

Lower CO2 emissions

Diesels have a bad reputation when it comes to the environment. Although older diesel engines do give off harmful emissions, newer models are much cleaner and more efficient. They also release less harmful CO2 into the atmosphere than petrol engines. 

Cons of diesel 

More expensive

Thanks to their more complex tech, diesel cars are usually more expensive to buy. On top of that, per litre, diesel is pricier than unleaded petrol. However, with the fuel crisis, petrol and diesel have recently become closer in cost.

Not suited for short trips 

If most of your journeys are just popping to and from town, a diesel might not be for you. Modern cars have a diesel particulate filter (DPF) to reduce emissions which doesn’t have time to heat up and work properly on short, low speed trips. Too many of these journeys can block the filter and cause engine problems. 

Air quality

Typically, diesel engines release more harmful emissions like sulphur, soot and nitrogen oxide (NOx) which affect air quality. Poor air quality has been linked to health issues like cancer and breathing problems.  

AdBlue 

AdBlue is a brand of diesel exhaust fluid that helps to reduce NOx emissions. This is an extra cost for diesel drivers as it must be topped up regularly. Most cars will have a display that lets you know when it needs refilling but how often depends on the car, your driving style and the size of the tank. Never let your car run out of AdBlue as it will reduce power significantly to keep to legal levels of NOx. 

Pros of petrol 

Less expensive 

Petrol cars are often cheaper to buy than diesel alternatives. And with cheaper prices for unleaded fuel, it costs less to fill them up. However, diesels tend to be more reliable and last longer so you may have to shell out more money to fix or maintain a petrol car.  

Good for short trips 

Petrol is a great option for people who are looking for a simple run-around. Without a DPF to worry about, petrol cars are perfect for short journeys and are economical when it comes to urban driving. 

Less air pollution 

Petrol engines don’t affect air quality in the same way as diesel engines. This is because they don’t emit the harmful chemicals like sulphur, soot or NOx. 

Cons of petrol 

Not as fuel-efficient 
 

Petrol engines are not as fuel-efficient as diesels as they work in a higher engine revs range and require more gear changes to speed up. If you drive long distances – especially on the motorway where you average high speeds – you may end up spending more on fuel. 

Higher CO2 emissions 

Petrol engines actually release more CO2 into the atmosphere than diesel cars. CO2 is the main culprit in global warming which is why the government is pushing buyers towards greener hybrid and electric cars. 

Which lasts longer petrol or diesel cars? 

Now you know the benefits, the biggest question is which engine is likely to last longer. The answer is diesel. Cars with a diesel engine usually clock up significantly more miles before they fail or need significant work. That’s because diesel lubricates the engine while petrol wears it out faster. 

Conclusion 

As with many things, there are upsides and downsides to both. Try to focus on what you personally need. Do you travel regularly? Are your journeys long or short? Is the environmental impact a big factor? Use these questions to guide you when buying your next car and remember, if you want to think ahead, you could even take the plunge and go all-electric.