Be prepared for E10 fuel

The introduction of E10 petrol at UK forecourts this summer could cut transport CO₂ emissions by 750,000 tonnes a year – the equivalent of taking 350,000 cars off the road, or all the cars in North Yorkshire.

However, many owners of classic cars have noticed some effects. First, ethanol softens or erodes glass-fibre, many plastics and rubber hoses. Fuel lines and GRP fuel tanks (eg. on motorcycles) can spring alarming leaks, while O-rings or diaphragms in carburettors and fuel pumps may fail.

Second, it’s hydroscopic, meaning it soaks up water and water vapour. This can speed up corrosion of non-stainless fuel tanks and pipes. It also ruins the paper element in fuel filters.

Third, it separates from the petrol itself after a relatively short storage period – months rather than years – leaving the petrol floating on a layer of watery, silty ethanol at the bottom of the tank.

Ethanol also has a corrosive effect on aluminium and some other non-ferrous metals and may also dissolve some of the varnish and rust in your fuel system.

Consider a few sensible changes. Replacement of the fuel lines (even copper ones) with ethanol-proof hose is affordable for most. It should be rated safe to E15 standards, not just E10. Ethanol-resistant fuel filters are harder to find. In the short term be prepared to change traditional in-line filters regularly.

Vehicles with glass-fibre fuel tanks are very unusual but any such installation needs replacing with stainless steel. If your tank is rusty and prone to leaks – perhaps repaired with epoxy or an internal tank sealant – now could be the time to make a similar investment. Also check the pipe from the filler neck to the tank itself; if it’s an old rubber item, replace it.

There’s also the issue of fuel separation. If your camper van gets year-round use it’s not a problem but for winter storage, you could try one of the fuel treatments.

You can check whether your vehicle is approved to use E10 petrol using the government’s E10 vehicle checker, which covers cars, motorcycles and mopeds.