Diesel vs Petrol: Which Car Type is Right for You? [2024]

Choosing between diesel and petrol cars has become a crucial decision for UK drivers. With advancements in technology, changing environmental regulations, and fluctuating fuel prices, understanding the differences between these two types of engines is more important than ever. 

The choice isn’t just about performance or fuel efficiency—it’s about finding the vehicle that best aligns with your lifestyle, driving habits, and budget. This guide will help you understand the difference between diesel vs petrol cars and highlight their pros and cons.

Factors to Consider for Your Next Car

Several factors must be considered when buying a vehicle, including initial costs, fuel costs, and more. Most people tend to lean towards petrol cars, but diesel cars also have advantages.

Let’s look at the significant differences between petrol vs diesel cars by analyzing these factors:

Purchase Price

Generally, diesel cars cost more than their petrol equivalent. So, when it comes to purchase price, petrol cars win this round. For example, a petrol BMW 520i in M Sport trim had a recommended manufacturer price of £44,980 in August 2022, while the diesel 520d M Sport was priced at £46,080.

Another good example is the Ford Focus Titanium X petrol car with a 1.0-liter EcoBoost engine. In 2021, this vehicle’s starting price was around £24,000, while the diesel version with a 1.5-liter TDCi engine cost approximately £26,000.

This higher purchase price for diesel cars is attributed to stronger engines, which use high-pressure fuel compression and additional emission-control systems, such as diesel particulate filters and AdBlue.

Considering a diesel vehicle? You have to be prepared for upfront costs.

Running Costs

Another factor to consider is running costs. After purchasing your preferred vehicle, you will encounter monthly running costs, so which is preferable? If we compare fuel economy only, diesel vehicles will take the lead here.

Diesel fuel is more expensive than petrol, but their cars are typically more fuel-efficient. This offers savings in fuel consumption, especially for high-mileage drivers. However, the price difference between petrol and diesel can fluctuate, impacting overall running costs.

Note that running costs include much more than just fuel costs. You should also consider servicing and maintenance too. Diesel engines generally have higher maintenance costs due to their complexity and the need for more frequent maintenance than petrol engines. This makes petrol ones a budget-friendly choice for many buyers.

We also need to consider the costs of AdBlue. Modern diesel cars should have a system called Selective Catalytic Reduction, which requires a regular supply of AdBlue. It’s affordable at £5 per 3,000 miles, but it adds to the running costs of diesel cars and must be considered.

Insurance

What car types cost more to insure? Diesel or petrol cars? The costs of car insurance depend solely on the size of the engine and its market value, not on the fuel type. However, it is worth considering.

Due to their complexity, diesel cars have larger parts and cost more to repair or replace than their petrol counterparts. Therefore, buying a diesel car may result in a higher premium from your insurance company.

Emissions

When it comes to air pollution, petrol and diesel vehicles breathe differently. Emissions are divided into two types – CO2 emissions and NOx. Diesel cars are known to produce less CO2 emissions than petrol cars.

A diesel car is the best option if you are environmentally conscious and want a smaller CO2 footprint. This can also benefit long-distance highway driving, where CO2 emissions become a more significant concern.

However, the tables turn regarding NOx (Nitrogen Oxide). Diesel cars emit NOx which has a major effect on air quality and the environment. If not managed properly, it can cause smog and respiratory problems. That’s where AdBlue comes in to neutralize the effects of NOx.

So, if you’re doing a lot of city driving, you can consider getting a petrol car and avoid Nox, and if you are more of a highway driver, a diesel vehicle will help reduce your CO2 footprint.

Tax

Tax rates for diesel and petrol vehicles vary, largely depending on when the vehicle was first registered and its emissions standards. Here’s a breakdown of how tax rates are applied:

• Before April 2017: Tax rates are based on CO2 emissions. Vehicles registered before this date and emitting no more than 100g/km of CO2 are exempt from car tax. Due to their lower emissions, both diesel and hybrid cars from this period benefit from lower tax rates.
  
  
• After April 1, 2017: Vehicles registered from this date are taxed based on their emissions for the first year, with subsequent years charged at a fixed rate of £155 per year (£145 for hybrid cars). Only zero-emission vehicles are exempt from this annual charge.
  
  
• After April 1, 2018: Diesel cars registered from this period must meet the Euro 6d standard to avoid higher first-year tax rates. Those that do not meet this standard face increased taxes to reflect their higher NOx emissions.
  
  
• After January 1, 2021: Diesel cars registered from this date must comply with the Euro 6D standard. These vehicles are subject to a fixed annual tax rate, but compliance with the latest emissions standards helps mitigate higher charges.

Diesel cars meeting the latest standards benefit from lower taxes, but older diesel models or those with higher emissions face steeper charges. Petrol cars generally have more predictable and often lower tax rates, making them a more straightforward option for many buyers.

Driving and performance

Diesel engines are renowned for superior torque, especially at lower revs (5,000 rpm maximum). This torque translates to strong pulling power and efficient highway cruising, making diesel cars particularly appealing for long-distance drivers and those who frequently travel on motorways.

The high torque also means diesel vehicles often excel in towing capacity, making them popular for towing trailers or caravans.

On the other hand, petrol engines are generally smoother and more responsive (with a maximum rpm of 6,500), offering many a more enjoyable driving experience. They tend to be quieter and produce less vibration, making a more comfortable ride. Petrol cars also usually have better acceleration and higher top speeds, appealing to drivers who prioritize performance and driving pleasure. 

Now that you have the basics of petrol and diesel cars, you can tell which vehicle will better suit your lifestyle, needs, and budget. The next section shows the pros and cons of diesel vs. petrol cars.

Diesel vs Petrol Cars: Pros and Cons of Diesel Cars

Pros of a Diesel Car

• Better fuel efficiency
• Better for long journeys and towing
• Covers more miles before refueling
• Low CO2 emissions
• Produce more torque
• Longevity and durability

Cons of a Diesel Car

• More expensive to buy
• Higher maintenance and repair costs
• Higher levels of NOx emissions
• Make lots of noise and vibrations

Petrol vs Diesel Cars: Pros and Cons of Petrol Cars

Pros of a Petrol Car

• Lower purchase price
• Smoother and quieter operation
• Better acceleration and performance
• Lower maintenance and repair costs
• Less complex emissions control systems
• Generally, more fuel options are available

Cons of Petrol Cars

• Lower fuel efficiency
• Higher CO2 emissions
• Less torque, especially at lower revs
• Shorter engine lifespan compared to diesel
• Higher running costs for long-distance drivers
• Potentially higher fuel costs depending on market conditions

Should I buy a used car in the UK?

If you have decided to buy either a petrol or diesel car, you also need to determine if you want to buy a brand new car or simply get a used one. This decision falls to your budget. If you can afford a new one, then, why not? However, to buy a used car, you must get a car history report for the vehicle you are interested in.

A car history report gives full access to past or historical records and registration information. You can even check the vehicle’s ownership history and be sure you’re not falling into one of those UK car-buying scams.

What can you find in a car history report?