The UK took a significant step towards environmental sustainability in 2021 by making E10 fuel the standard unleaded petrol at fuel stations, aligning with the government’s broader push for greener energy solutions. Although this contributes towards reducing carbon emissions, the transition has raised numerous concerns for classic car owners.
While it might be conducive to a more eco-friendly future, it brings new challenges for people driving cars designed long before the introduction of ethanol blended fuel.
What is E10 fuel?
Containing 10% bioethanol and 90% petrol, this blend is designed to improve society’s sustainability efforts. Bioethanol, derived from renewable sources such as plants, sugars and biomass, helps lower CO2 emissions.
The UK government has projected that the switch to E10 will reduce emissions by around 750,000 tonnes annually, equating to taking 350,000 cars off the road. This represents significant environmental benefits.
On the other side of the equation, the impact on older cars has been a point of concern. Before E10, the most common petrol grade in the UK was E5, containing just 5% ethanol. For most modern cars, it’s a good fit, but for vintage vehicles, the introduction of E10 has the potential to cause a range of issues.
Does E10 fuel damage engines?
When considering the use of E5 or E10 fuel, experts suggest that E10 can cause problems for older cars, as their components weren’t designed to withstand the higher ethanol content. Being hygroscopic, ethanol absorbs water, which can cause deterioration of classic vehicles over time. It accelerates the corrosion of metal components including fuel tanks, lines, carburettors and other parts.
Ethanol can also degrade rubber components, such as seals and gaskets, leading to leaks and potentially more serious damage. While it can be an effective cleaning agent in some modern vehicles, it can cause a build-up of sludge and deposits inside fuel lines, carburettors and fuel filters when compatibility is a risk. This can clog the whole fuel system, reducing performance and potentially leading to eventual engine failure.
Classic cars being run on E10 might experience rough idling, poor fuel economy, or even misfires, particularly if the fuel system hasn’t been properly modified to accommodate ethanol’s different combustion characteristics. When vintage vehicles are stored for extended periods, it can lead to phase separation. This occurs when water and ethanol separate from the petrol, potentially causing fuel contamination and engine problems when the car is started again.
Should I use E10 fuel additives for classic cars?
The risks posed can be significant and the effects can vary, depending on the vehicle’s age, the materials used in its construction and how well the fuel system has been maintained. Fuel additives are designed to help mitigate some of the issues. They can typically prevent corrosion and help protect the metal and rubber parts of the fuel system.
By stabilising the ethanol content, certain additives can reduce the likelihood of phase separation and the problems of engine misfires and poor performance. Some additives also offer extra lubrication to protect rubber parts from degradation. They can help stabilise the fuel, improving performance after storage by ensuring better combustion.
However, even if a vintage car has been retrofitted with modern, ethanol-resistant components, long-term exposure to E10 may still cause issues, especially in vehicles that are not regularly used or maintained.
Are there safe uses?
Despite the potential risks, E10 is not an outright danger to all classic cars, especially those that have been upgraded to modern standards. Many enthusiasts have found that with the relevant modifications, it can be used safely.
However, there are a few conditions to keep in mind. Regular use of the vehicle is recommended to prevent fuel stagnation and the potential for phase separation. Classic cars that are driven frequently are less likely to experience the corrosion and deposit build-up that can occur when they sit for long periods with ethanol in the tank. Additives can mitigate some of the negative effects, although they’re not a complete solution.
The government has introduced a compatibility checker to help motorists determine whether their vehicle is suitable for E10 fuel, but it doesn’t cover all cars, especially those made before the 2000s. Vintage vehicle owners in particular may find that their model isn’t listed, meaning they’ll need to make a more detailed assessment, or consult a specialist.
Professional advice
Several organisations, including the Federation of British Historic Vehicle Clubs, the RAC and AA, have issued advice to try and help. The consensus is clear: if your car isn’t explicitly listed as compatible with E10, it’s best to avoid using it. Many experts recommend sticking to E5 fuel or using fuel additives designed for classic cars to protect your pride and joy.
The FBHVC has been particularly vocal in raising awareness about the potential issues. The club advises owners to be cautious when filling up and to consider upgrading their fuel system if they plan to use E10 regularly. It concedes the switch isn’t entirely out of the question for vehicles that have a modified fuel system. Regularly cleaning the carburettors and fuel tanks can help too.
Specialist insurance providers Hagerty and Footman James advise that classic vehicle owners should generally avoid it due to the risks of damaging system components.
What if I accidentally fill up with E10?
The answer is don’t panic! The effects on your vehicle won’t be immediate and there are several steps you can take to minimise any potential damage. Don’t store your car for a long period with it still in the tank. It’s safer to drain the fuel tank, or to drive until it’s empty.
If you’ve filled up with E10 and don’t want to waste your money, consider fuel additives. Keep an eye on performance, and if your car starts running rough, misfiring, or exhibiting poor fuel economy, stop driving, empty the tank and have an expert service the carburettors and fuel system.
While it brings environmental benefits, it may cause damage to older vehicles if not carefully managed, so classic car owners should take the appropriate steps to minimise the risks. Ultimately, while the shift to E10 is part of a need for greener energy, it requires a thoughtful approach to ensure that your cherished vehicle remains in good condition.
