Why do you favour petrol over diesel?

Reader questions What Car?'s preference for petrol-engined cars over diesels in many car classes...

09 April 2019
New Volvo XC40 vs BMW X1 vs Volkswagen Tiguan

Could you please explain why your new car reviews consistently favour petrol cars over diesels, even when it comes to SUVs? Diesel cars’ CO2 emissions are better than petrols’, as are your True MPG figures. 

The NOx emissions of the latest diesel cars that are fitted with AdBlue or other cleaning systems are also comparable to petrol counterparts'. Granted, diesels’ particulate filters do require regular longer journeys on faster roads, but this shouldn’t put off lots of people from buying a diesel.

Diesel particulate filters - everything you need to know

And if you add other characteristics of diesel engines, such as better torque and longevity, I’m somewhat baffled as to why an independently minded car magazine doesn’t recommend them more often. 

Richard Green

What Car? says…

We don’t favour petrol over diesel in principle; indeed, we still recommend an awful lot of diesel engines, including in our overall 2018 Car of the Year, the Volvo XC40.

Petrol is the obvious choice in small cars, because drivers of these usually won’t do enough miles to justify the higher price of a diesel. And with the progress of turbocharged petrol engines, this can also be true for larger hatchbacks and mid-sized SUVs. 

We also consider that many of these are run as company cars, and while diesels emit less CO2, they also incur an extra 4% on BIK tax. Plus, diesel models usually cost more than petrols, pushing up their P11D values, which the tax is calculated from.

It’s only when you get to large saloons and SUVs that diesel becomes the default. Often, a petrol engine won’t provide the flexible performance of a diesel in these, plus there’s a large disparity in efficiency.

Read the full 2019 What Car? Awards results

Read more questions and answers from Askwhatcar 

For all the latest reviews, advice and new car deals, sign up to the What Car? newsletter here


Buy a new car with What Car?

Before you buy, visit What Car?’s new car deals section.

We have discounted deals on most new cars on sale, so you're never far away from finding a new car deal in your area.

It's all based on Target Price, which is the price we think you should pay based on research by our team of mystery shoppers, and the best discounts they can achieve.

If you’re still not sure then our deals team can help; call them on 03302 216207 – lines are open from 8am until 10pm seven days a week.

Related cars