E10 petrol is here, but what does it mean for the aftermarket?

E10 unleaded petrol is now the standard grade of petrol in the Republic of Ireland, replacing E5 at the start of April.

Introduced in Great Britain in September 2021, before being rolled out across forecourts in Northern Ireland last November, E10 is said to provide fewer kilometres per litre due to it containing fiver per cent more ethanol, compared to E5.

E10 is, however, made up of 10 per cent renewable ethanol, meaning it should help reduce CO2 emissions in Ireland and move closer towards low- and net-zero carbon emissions.

So what does E10 mean for the automotive aftermarket?

Well, E10 petrol is known to pose a risk of damage to older cars. Its higher bioethanol content is also somewhat corrosive to rubber parts, gaskets, seals, metals and plastics, which causes engine damage, so it could dislodge deposits in older engines and fuel systems, causing blockages over time.

E5 petrol corresponds to the fuels SP95-E5 and SP98-E5. E5 means that the petrol contains up to five per cent bioethanol, blended with unleaded 95 or 98. E10 petrol, or SP95-E10, is unleaded 95 enriched with 10 per cent bioethanol.

If a car is accidentally filled with E10 when it should get E5, some of the vehicle’s internal components may suffer as a result. The extra solvents in the fuel can cause damage to the fuel pumps, lines and carburetors, especially in the long term.

According to the Department of Transport, around one-third of fossil fuelled cars in Ireland are petrol. It says all vehicles can operate on an E10 petrol blend, and it is safe to do so, but in some older vehicles pre-2011 (mainly pre-2003/pre Euro V standard which were not manufactured with certification for E10 use), sustained use may result in more frequent maintenance, for example of engine seals and hoses – meaning more trips to a workshop.


E10 has been the standard grade of petrol in Britain for just over 18 months now. E5 fuel is now considered ‘super’ grade, and although all major petrol stations still stock it, it’s more difficult to come by at rural or remote stations, who may only stock E10.

A classic car insurer in the UK last year conducted a survey of 41 classic car owners asking them about their experiences finding E5 fuel. In the results, 66 per cent said they have had trouble finding E5 fuel since E10 was introduced there, while the rest had no problem accessing it.

While the survey may be small, it highlighted how finding E5 fuel is a big deal for those who drive classic cars in the UK – and this may prove to be a problem here in Ireland too.

There will also be no price incentive for E10 petrol like in the early 2000s, when the ethanol-based E85 fuel was introduced here.