Is it worth using premium car fuel?

An AI-generated image of a superhero using a petrol pump with premium fuel.

Regular readers will know that I’ve been having some car issues of late, which has seen it spending a lot of time in the garage being fixed. So far, it’s been running okay for the past couple of weeks, and so I’m very hopeful that there’ll be no more expensive repairs due for a while at least.

At its most recent garage visit, to have the particulate filter cleaned, the mechanic asked whether I was using supermarket fuel. Because, in his view, this was why I was having problems with the filter. Premium fuels – the ones that you pay extra for – have additives which claim to help clean out your car’s fuel line. As well as preventing the filters getting full, they should – in theory – boost efficiency and result in you getting more miles per gallon of fuel. Once the car was fixed, I was therefore advised to stick to premium diesel for a few months.

This was a topic that the excellent BBC Sliced Bread podcast covered back in January last year. There’s also some information from Auto Express and Which? (for which you may need a Which? subscription to read). The consensus seems to be that premium fuels can help keep a car running better, but they only need to be used occasionally. Supermarket fuel – or at least, supermarket petrol – should be fine to use most of the time. And it is generally cheaper than even the basic fuel from branded petrol stations.

As instructed by the mechanic, I filled up with Shell’s ‘V-Power’ premium diesel earlier in the week. You pay quite a bit more – it was £1.76 per litre, as opposed to £1.58 per litre for their standard diesel. For context, £1.53 per litre is the current cheapest price locally for diesel, according to My tank was low – the fuel warning light had come on – so I paid almost £100 for a full tank. This was £12.65 more than if I’d filled up with regular diesel at the cheapest nearby petrol station.

We’ll see if it makes a difference. Although my car does track its fuel usage in miles per gallon, it doesn’t use a moving weighted average and so it’s prone to fluctuations, making it a bit useless. My car is over 11 years old, and so anything to clean out the fuel lines and injectors is welcome.

I’ve also used some engine cleaner from Halfords; you put this in once your tank is below a quarter full (i.e. three quarters empty) and then take it for a decent drive until the fuel warning light comes on. It recommends that you use it around four times a year, and this may be a better option. Theoretically, it does the same job as the premium fuel, but costs £10-20 each time. Overall, that works out cheaper than paying more for premium fuel.

So, in honour of Betteridge’s law of headlines, the answer to the question ‘is it worth using premium car fuels?’ is probably no. You can use supermarket fuels, but maybe pop some engine cleaner in now and again – especially if you have an older car. Or go electric – I’m sure our next car will either be a plug-in hybrid or a fully battery electric vehicle.