Ask Honest John Question of the Week: Is supermarket fuel safe to use?

David Ross, Editor
Fri, 23 Aug 2024

Dear Honest John,

"I have read recently it is not good to use petrol from supermarkets as it does not have the same additives as regular garages, and can lead to engine problems over time. Is this true?"

- RS

Dear RS,

There are a number of myths about supermarket fuel, a lot of which relate to a poor batch of fuel supplied to a national supermarket chain a couple of years ago.

However, the fuel you find in supermarkets has the same regulations as premium sellers. And they're held to the same quality and safety standards. So, although it's cheaper, you can be reassured that you aren't purchasing a harmful or unsafe product.

Premium petrol and diesel fuels, frequently found at branded fuel stations but also some supermarkets, may offer additional benefits. A higher octane petrol may bring small benefits in performance and economy if your car is designed to work with them and can adjust the ignition timing to suit.

Premium fuels also often contain additives which are designed to reduce wear and help keep your engine cleaner, which may help your engine in terms of longevity. However, it is worth bearing in mind that there is no independent evidence to support this, even if anecdotally many car owners say their vehicles run better on premium fuels.

Essentially it is a matter of balancing the cost saving of supermarket fuels against the potential benefits of a premium option. Using supermarket fuel would not cause engine problems that would otherwise be avoided by using a branded regular fuel, while it is a personal choice over whether the possible benefits of a premium fuel are worth the higher pump price.

Ask HJ

Is supermarket fuel poor quality?

Is supermarket fuel quality being compromised due to the large mark up they are being allowed to charge? My 25k mile Audi Q7 engine light came on recently and turned out it was a Nox sensor failure, Strange thing is whilst in the Audi dealer I was told it would take a few days to get the part as there was a run on failures so parts were low. Only a week later my brother rang to say same fault on his Audi Q5. Now these parts aren't cheap, £800+, fortunately my car is under warranty. Is it possible to prove what caused the damage and how can this be avoided in future?

There is no evidence to suggest that supermarket fuel is inferior quality, as they conform to the same British standards as any other fuel sold and are supplied by many of the same large refineries. Premium fuels such as Shell V-Power may offer additional benefits thanks to additives designed to reduce wear, but you should experience no problems from using standard fuels.

Answered by David Ross

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