Should I Buy a Diesel Car?

One of the trickiest choices new car buyers have to make

Should I buy a diesel car? Possibly the hardest decision you’re going to have to make may not be the type of car, the make or even the colour, but what you fill it up with. Diesel or petrol, petrol or diesel – it’s become a big question for car buyers in recent years with the technological advances in diesel-engine technology, as well as the increase in prices at the pumps and the not-so-unnoticeable Dieselgate. What was once an easier question to answer has become much more down to a range of factors rather than just mileage alone. In the 1990s and even early 2000s, if you drove a lot of miles, the only real choice was a diesel, because diesels were inevitably more efficient and lasted longer, due to the lubricating effects of the fuel itself.

Today’s diesel engines are able to offer incredibly high miles per gallon (mpg), while simultaneously being cleaner and a lot more refined. They’re smooth, quiet and, although they may cost more initially, the idea of low or no road tax along with more miles per tank and less fuel fill ups makes diesels a tempting choice.

Should you buy a diesel or a petrol car? Follow our guide below and find out if a diesel really makes sense for you.

Things to think about:

Before we look at the pros and cons of buying and owning a diesel car, there are a few things you need to consider. Diesels work differently from petrol engines; they deliver their power quicker but often require to be driven differently. Plus, there’s the higher cost of servicing to consider, as well as the environmental impact caused by choosing the black pump over the green. So before you go for diesel based on the temptingly high efficiency alone, consider:

  1. Am I prepared to pay more for a diesel?
  2. Am I prepared to pay for higher servicing costs?
  3. Am I prepared to pay more at the pumps?
  4. Do I travel enough miles for a diesel to make financial sense?
  5. Do I travel shorter journeys or longer journeys?
  6. Would I prefer the low-revving torque of a diesel to the higher-revving petrol?
Pros and Cons of Diesel Cars

Diesel Pros

1. MPG 
Diesels tend to achieve much higher miles per gallon than petrol engines. Certain models like the Citroen C4 Cactus BlueHDi state they’re capable of up to 91mpg. Real-life mpg figures tend to be lower, as manufacturers use laboratory conditions to achieve these figures, but on paper this does look impressive.

2. Lower CO2 emissions 
There’s a lot of talk about diesels and the harmful gases they emit, but the main gas of interest to cost-conscious buyers is CO2. A car’s carbon dioxide emissions are rated on a scale – the ‘dirtier’ the car, the more you pay in road tax. Generally, the larger the engine and the larger the car, the more CO2 it will emit. However, due to advances in technology, you’ll also tend to find newer diesels emit far less CO2 than older models. The Citroen C4 Cactus mentioned earlier, for example, emits just 82g/km of CO2, below the magic 100g/km at the bottom of the road tax scale.

3. Lower road tax 
As diesels tend to emit less CO2, they are usually subject to much less road tax than petrol engines. Any models that emit 99g/km of CO2 or less instantly mean you pay zero road tax. Own a car for a few years and this could add up to a saving of a few hundred pounds.

4. Torque
Put simply, torque is the power delivery. Diesels tend to require less work to get this power. Typically, at around 2,000rpm on a diesel when the turbo kicks in, you receive a surge of power. This makes pulling away from traffic lights effortless and a lot of drivers prefer the initial ‘kick’ that a diesel car produces. Petrol cars tend to require some revving to get to that power and even then it’s not delivered in one big lump.

5. Resale values
Diesels tend to hold on to their prices better on the second-hand market. The premise that diesels are more reliable, can go for hundreds of thousands of miles and generally seem to cost less to run make them a tempting buy. High mileage diesels are generally more acceptable to used car buyers, due to the fact that these are usually expected to have been ‘motorway miles’, meaning the car has sat at a steady speed for longer periods of time. This is favoured as it causes less wear and tear.


Diesel Cons

1. Environment
Burning any form of fossil fuel is going to be harmful to the environment, but diesel is particularly bad. Nitrogen dioxide, sulphur dioxide, carbon monoxide and many more toxic gases are released, causing environmental and health issues. It’s recently been announced that cities like London are considering a diesel tax or banning diesels from the city centre altogether.

2. Warm up time
Diesels take longer to get up to optimum operating temperatures. Consequently, if you only do a lot of short journeys, you may hardly notice the frugality that a diesel promises.

3. Initial cost
Diesel engines are getting better and better but this requires development. While the manufacturer absorbs some of the cost, the additional technology advancements requires to make diesels cleaner and more efficient means a higher price on the forecourt.

4. Diesel fuel cost
The price difference between petrol and diesel is closer than ever when it comes to filling up. Diesel has historically always cost more, but with the uncertainty over the future of the fuel, this price difference may not always stay the same.


Choosing whether or not diesel is the fuel to choose depends on a number of factors that only you can answer. Gone are the days where you could simply calculate how many miles you drive per year and if it’s more than 25,000 miles choose a diesel as there are far more reasons to choose a diesel other than cost. The promised efficiency of a diesel may be the main selling point for most customers, but the higher resale values and the way the torque is delivered by a diesel are both equally important and may be enough to sway you away from petrol.

The only way for you to choose whether diesel is right for you is to weigh up the pros and cons based on what you want from a car and how much you want to spend.

Think about these points:

  • I want to be able to drive 500 or more miles on a single tank of fuel.
  • I want a good return for my car when I come to sell it.
  • I want running costs to be as low as possible.

If you answered yes to most of the above, then diesel is probably the fuel for you.

Have questions about diesel cars?


Disclaimer: This page is intended to provide information only, it is not, and should not be taken to be advice or an offer of credit. The information is subject to change without notice. Every effort has been made to ensure the accuracy of the information on this page and manufacturers or dealerships may vary the products or specifications of the products they offer. For full terms and conditions contact the relevant manufacturer or your local dealer. Imagery is a visual representation and may not represent the exact products. Please ensure you can afford the monthly payments before signing any contractual agreement. You will not own the vehicle until all payments have been made. Any finance or offers mentioned are not available in conjunction with any other offer and may be varied or withdrawn by the manufacturer or dealer at any time.

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