Diesel or petrol for a used company car, which makes better financial sense?

A diesel is not automatically cheaper just because it uses two litres less fuel per 100 km. Nor is petrol necessarily the sensible choice simply because most journeys are in town. The right answer depends on the routes the car will cover, annual mileage, vehicle age and what downtime would cost the business.

The most common mistake? Looking at fuel consumption alone.

When buying a used car, you need to consider the full picture: lease payments, fuel, expected servicing, insurance and the vehicle’s likely value at the end of the agreement. Only then can you tell whether diesel or petrol will genuinely work out better for the business.

Annual mileage is only the starting point

For years, the rule of thumb was simple: diesel above 20,000–25,000 km a year, petrol below that threshold. It can still be a useful guide, but treating it as a ready-made answer leads to poor buying decisions.

Two cars may each cover 25,000 km a year in completely different conditions. One travels 100 km on an expressway every day. The other makes a dozen short trips around Warsaw, Kraków or Poznań, with the engine rarely reaching its proper operating temperature.

A diesel makes sense in the first case. In the second, it may soon develop problems with the diesel particulate filter, EGR valve or SCR system. How the mileage is accumulated matters more than the number on its own.

Where a diesel works best

Diesel engines are at their best on regular, longer journeys. A sales representative travelling between regions, a field technician serving customers in several cities or a construction company driving to remote sites can make proper use of their strengths.

Take the Škoda Octavia 2.0 TDI. Driven calmly outside town, it may return around 4.5–5.5 litres per 100 km. An Octavia 1.5 TSI under similar conditions will typically use around 6–7 litres. At 35,000 km a year, that difference starts to show in the accounts.

The same logic applies to cars such as the Volkswagen Passat and Škoda Superb, as well as vans including the Ford Transit Custom. A large body, regular operation under load and long-distance driving all favour diesel. Torque matters too, particularly when the vehicle carries goods or tows a trailer.

What lower fuel consumption is really worth

Consider a straightforward example. A petrol car averages 8 l/100 km, while a comparable diesel uses 6.5 l/100 km. If both fuels cost PLN 6.50 per litre, the difference is PLN 9.75 for every 100 km driven.

At 15,000 km a year, that saves approximately PLN 1,460. At 30,000 km, the figure rises to around PLN 2,925. These savings can then be compared with the difference in purchase price, monthly lease payment and likely servicing costs.

If the diesel costs PLN 10,000 more and the company plans to keep it for only three years, the fuel savings may not recover the premium. The calculation changes when both cars are similarly priced or the business covers 40,000–50,000 km annually.

Official fuel-consumption figures should not be taken at face value either. A loaded van, an SUV on wide tyres and an estate car used mainly on motorways will produce very different results. A sound calculation should use real-world consumption reported by owners of the particular model, with a modest contingency added.

Short journeys change the calculation

Petrol is generally the lower-risk choice when a car makes frequent short trips. This applies to sales staff working within one city, administrative employees, technical teams handling local jobs or a business owner driving only a few kilometres to the office.

Suitable options might include a Toyota Corolla 1.6 petrol or 2.0 Hybrid, a Škoda Octavia 1.5 TSI, Volkswagen Golf 1.5 TSI or Kia Ceed 1.5 T-GDI. A petrol engine warms up more quickly and is better suited to journeys that would not allow a diesel particulate filter to regenerate properly.

That does not make petrol engines maintenance-free. Modern units may have turbochargers, direct injection, gasoline particulate filters and complex electronics. The specific engine version and its history matter far more than the label on the fuel cap.

A car with documented oil changes every 10,000–15,000 km may be a safer purchase than a newer example maintained at the manufacturer’s maximum service intervals. This is particularly true if the previous owner mainly used it in town.

A diesel can save money. It can also produce a large repair bill

With a diesel that is several years old, high mileage is not always the greatest concern. Missing records, mileage fraud or a pattern of use unsuited to the engine can be more worrying.

Before arranging finance, have the DPF, injectors, turbocharger, EGR valve and AdBlue-based SCR system checked. One fault does not necessarily rule out the car, but it should be reflected in the price. Repairing the injection system or replacing emissions-control components can easily cost several thousand PLN.

Downtime matters as well. If the vehicle is used by a field-service team and generates revenue every day, three days off the road may cost more than the repair itself. A business with one vehicle should therefore take a more cautious approach to risk than a larger fleet with replacement cars available.

Conversely, a well-maintained diesel with 140,000 km, most of it covered on motorways, may be in better condition than an 80,000 km example used exclusively for short journeys. The odometer never tells the whole story.

Purchase price and monthly payments matter too

Comparing engines without looking at the price of the actual cars is largely academic. On the Polish used-car market, a well-equipped diesel can sometimes cost less than a petrol version of the same age. The reason may be as simple as a greater supply of ex-fleet vehicles.

The reverse also happens. A desirable diesel with an automatic gearbox and a fully documented service history may hold its value, while the petrol version is noticeably cheaper. The difference in monthly payments can then exceed the fuel savings.

For example, suppose the diesel lease payment is PLN 220 net per month higher, while the company saves around PLN 170 a month on fuel. Lower consumption alone does not justify the diesel. Expected resale value, warranty cover and the condition of both cars still need to be considered.

With an operating lease, the initial payment, finance term and final purchase option also affect the calculation. The same car will have a different monthly payment on a 36-month agreement than on a 60-month one. A longer term, however, also increases the chance of age- and mileage-related repairs.

A practical decision guide

If the car covers 30,000–40,000 km a year, most journeys exceed 30 km and it regularly travels under load, diesel is the natural candidate. I would not buy one without diagnostics and a verified service history.

At up to around 15,000–20,000 km a year, with mainly urban use and frequent stops, petrol will usually make ownership less troublesome. Even if it uses slightly more fuel.

Between 20,000 and 30,000 km, there is no automatic answer. Compare two actual cars. Age, price, monthly payment, equipment, mechanical condition and the type of journeys they will cover reveal far more than general opinions about either fuel.

Vans are a separate category. Diesel still tends to win because of model availability, driving range, torque and performance under load. There are fewer petrol alternatives, and their fuel consumption can rise quickly when the vehicle is fully loaded.

Choose the car first, then the fuel

With a used company car, a sound example matters more than the perfect specification on paper. A well-maintained petrol car with a complete history is a better purchase than a diesel of uncertain origin simply because the business exceeds the conventional 25,000 km threshold. The opposite is also true: it is difficult to justify a petrol car using two or three litres more per 100 km on regular motorway journeys if a verified diesel is available at a similar price.

Carmore lets you compare used cars and commercial vehicles, then calculate the net monthly payment for your chosen initial contribution, finance term and final purchase amount. The calculator shows how a difference in vehicle price affects the monthly budget. From there, you can compare the payment with expected fuel and servicing costs.

If a bank has declined your finance application or offered terms that do not suit the company’s cash flow, contact a Carmore adviser. We will review the available options without promising an approval before the figures have been checked. Numbers first. Car second.

Images (manufacturer press materials)

• Škoda Octavia Combi 2.0 TDI on an expressway, an image showing the conditions in which a diesel performs at its best; source: official Škoda press centre.

• Volkswagen Golf 1.5 TSI in urban traffic, suitable for the section on short journeys and petrol engines; source: Volkswagen Newsroom.

• Ford Transit Custom carrying a load or being used by a field-service business, illustrating the effect of payload on a commercial vehicle; source: official Ford Polska media resources or the Ford Media Center.

• Toyota Corolla in an office car park, illustrating a company car used mainly for local journeys; source: Toyota Europe or Toyota Polska press centre.

All materials should come from manufacturers’ official press centres and carry a licence permitting editorial use.