Toyota Auris – should I buy petrol, diesel or hybrid?

If you’re about to buy a new car, you’ve likely thought about what kind of engine you’d like. Almost all new cars are offered with a range of engines – typically petrol and diesel models, while a selection also offer a part-electric hybrid alternative.

Some buyers might assume that, because diesels and hybrids typically use less fuel than their petrol counterparts, those models will save them money in the long run. The question is – are they right? We’ve done the maths to help you pick the right powertrain for you.

Petrol vs diesel vs hybrid – monthly costs

Below, we’ve worked out monthly costs for the Auris, including fuel, tax and monthly finance repayments using examples from Toyota’s website. Fuel prices at the time of publishing are 110.54p per litre for petrol and 111.45p per litre for diesel, while monthly repayments are taken from Toyota’s representative finance example – in every case, a PCP arrangement over 36 months with a £2,000 deposit.

We looked at mid-level Icon trim fitted with either the 1.2-litre turbo petrol claiming an average of 58.9mpg, the 1.6-litre diesel returning 67.3mpg or the 78.5mpg hybrid. We also looked at three types of buyers – an 8,000 mile per year low miler, a mid-miler covering 20,000 miles per year and a high mileage driver averaging 30,000 miles per year.

Unsurprisingly, the more efficient the engine, the lower the monthly fuel costs across the board. Factor in the higher monthly repayments commanded by the more economical models, however, and those savings are reversed. Across a three-year PCP deal, the petrol is almost always the cheapest option thanks to its lower monthly repayments.

In fact, this trend is only undone by a hybrid owner covering 30,000 miles per year – something few hybrid Auris models and, indeed, drivers are likely to accomplish. If you only plan on keeping your car for the duration of its PCP deal, the basic petrol engine almost always works out as the cheapest option.

Why buy a hybrid or diesel?

So why bother getting one of the more efficient engines? Taking overall price into account, we can work out how long you’d need to own each model before the promised fuel savings actually make up the increased purchase price…

When viewed from this perspective, the financial reasons for choosing the more expensive and more efficient engines become more evident. As we’ve shown, the petrol is almost always cheaper over a three-year PCP deal but, if you’re planning on keeping your car for longer, diesel and hybrid models eventually recoup their extra purchase price through fuel savings – though this can take an awfully long time.

The time taken to recover the initial purchase price gets progressively shorter depending on the number of miles you cover annually. This means a very high mileage driver will see a benefit from a diesel or a hybrid model sooner than a low mileage driver. As a result, low mileage drivers are almost always better off going for the petrol option and only those who cover sufficiently high mileages and plan on keeping their car for long enough will see any tangible benefit from diesel and hybrid models.

Is this the full story?

No, but it’s a good reflection of many models across the market. Plenty of cars such as the Volkswagen Golf, Audi A3 and Toyota Yaris all offer petrol, diesel and hybrid powertrains and we’d expect very similar result in those cases, too.

While they might actually cost more despite using less fuel, there are other reasons why hybrid and diesel models might suit you. Diesels typically have plenty of pulling power – or torque – which makes them ideally suited to towing caravans, trailers or horse boxes. Diesels also typically favour running at constant speeds as you would on the motorway so, if the majority of your driving time is spent here, diesel might make sense.

Similarly, hybrid engines are much better suited to stop/start traffic in city centres. Where the efficiency of conventional engines tumbles at the constant acceleration and braking, the electric motors in hybrid models can make up for this drop in efficiency. This means those who spend almost all their time in the city might reap much higher fuel savings driving a hybrid as opposed to a petrol.

Finally, there’s a subjective quality to each engine that could sway your favour. Diesels tend to sound clattery which, to some ears, can spoil the car’s cabin ambience, compromising the ownership experience. Petrols, thanks to their different combustion process, typically sound smoother and quieter making them easier to live with. Hybrids are similar but many, like the Auris, feature CVT automatic gearboxes that cause the engine to become whiney when pushed hard. The best bet is to try each to see which you prefer.

So which should I pick?

The best way to pick the right engine for you is to look at the options within your budget and work out the monthly fuel and repayment costs as we’ve done here. Combine this with the mileage you intend to cover and the length of time you’re planning on keeping the car to decide which option makes the most financial sense.

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