Over the years, tightening emissions regulations have forced changes within the petrol industry and altered the formula of standard fuel. Leaded petrol disappeared from UK forecourts at the turn of the millennium, E5 biofuel was standardised in 2019 and in September 2021 the recipe of standard-grade unleaded petrol changed to double the content of renewable, non-fossil ethanol. This petrol is identified by the code E10.

While these changes are welcomed in order to help cut carbon monoxide emissions, ethanol-blended petrol can have a negative effect on a vehicle’s fuel system. How is that the case?

Ethanol is soluble in petrol but it is also hygroscopic, which means that it attracts and absorbs moisture from the air. Petrol, on the other hand, is immiscible, which means that it does not mix with water. So when moisture is attracted and absorbed into the ethanol it is eventually forced to separate from the petrol and sit at the bottom of your fuel tank. This can be especially damaging for cherished and classic vehicles that are taken off the road and stored over winter – months when atmospheric moisture levels are at their peak.

Classic Etha-Guard Plus is said to swiftly counteract ethanol’s hygroscopic nature, stabilising both E5 and E10 biofuels. It prevents moisture from saturating the ethanol and forcing it to drop out of safe suspension within the petrol, thereby protecting the vehicle’s entire fuel system against corrosion and acidity.

Classic Etha-Guard Plus ethanol stabiliser petrol additive

• Ethanol stabiliser protects existing fuel systems and enables the use of E5 (super unleaded) and E10 (regular unleaded) biofuels in vehicles with or without catalytic converters
• Prevents corrosion and acidity within the fuel system
• Counteracts ethanol’s natural hygroscopy while vehicles are in storage
• The two-in-one formula adds an Octimise-Plus friction modifier to improve acceleration by up to 3% and economy by up to 2%
• £14.95 for 250ml bottles or £12.46 each and free delivery when ordering six or more

Each 250ml bottle of Classic Etha-Guard Plus is designed to treat 250 litres of fuel, which makes it a cost-effective way of maintaining the internal health and well-being of all vehicles.

More information on this product can be found by heading to www.classicoils.co.uk/additives, while purchases can be made through the Castrol Classic Shop on www.classicoilsshop.co.uk. Check to see if your vehicle is affected by the switch to E10 petrol by visiting www.gov.uk/check-vehicle-e10-petrol