Premium unleaded petrol is higher in price due to it’s higher octane refinement and lower ethanol concentration – but is it actually better for your vehicle’s engine?
Is premium unleaded petrol worth the added expense? (stock) (Image: alvaro gonzalez/Moment via Getty Images)
We’ve all seen the different-priced pumps at petrol stations, but is premium fuel actually better for your car? Typically, E5, which is consider the premium ‘super unleaded’ option costs several pence more per litre than the standard E10 unleaded fuel.
The difference is in the ethanol content – E5 contains up to five per cent bioethanol, whereas E10 contains up to 10 per cent. Meanwhile E5 also has a higher octane rating and refinement, which adds to it’s expense. Now, a consumer expert has examined whether or not it’s worth us spending more when we fill up.
Asked by Which? whether premium fuel makes vehicles run better, senior researcher, Michael Passingham explained that is not the case.
“No – standard fuel has all the hydrocarbons and detergents your engine needs to run cleanly,” he explained.
Michael added that any differences would be “so minor” that they are “unnoticeable” while driving and indeed, at your vehicle’s annual service when mechanics check the engine.
“The only exception to this is cars where it specifically states in the manual that you need to use premium fuel, but at this point you will know that,” he said.
Stoneacre Motor Group back up this advice. However, they point out there are exceptions.
“If you have a regular car newer than 10 years old with mileage below 80,000, chances are there would be little benefit [of opting for premium fuel],” they advise online.
“However, if your car is outside the parameters, or has been feeling a little sluggish recently, you can try filling your next tank up with high-octane fuel to see if you notice any change.
“Retailers boast their premium fuel has additives to clean the whole fuel system of your car; this might be especially effective on carbon deposits inside the combustion chamber.”
As for diesel, premium options at your typical petrol station are less common. But where premium is an option, Stoneacre goes on to point out: “If you’ve just driven away in a brand-new diesel car, using premium fuel will not achieve anything as all the engine components are already clean and running smoothly.
“However, if you do high mileage in your diesel, it might be worth filling a tank with premium fuel once every six months. This will flush through the fuel system and help clean any build-up.”
Elsewhere, if you have just bought a second-hand diesel car it would be wise to use premium diesel the first time you fill up in order to give the fuel system a “good clean”, Stoneacre says.
The experts added: “But it’s certainly not worth the extra money to fill with premium diesel every time.”
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