Using the right car fluids has always been a hot topic with classic car enthusiasts. This is especially true now that E10 fuel has made its way to petrol stations across the UK.* As of 1 September, the government is encouraging us to use E10 fuel (instead of E5 fuel) unless you own a classic car.
But what’s the difference between E5 and E10 fuel? And what do classic car owners need to know about this shift?
*E10 fuel will become the standard petrol grade in Northern Ireland in early 2022.
What Is E10 Fuel and Why Is It Replacing E5 Fuel?
The switch from E5 to E10 forms part of the government’s pledge to cut CO2 emissions and curb climate change. This is because E10 uses a higher proportion of bioethanol (produced from renewable crops like grains, waste, wood and sugar beet) than E5. Up to 5% of E5 fuel is renewable ethanol. Meanwhile, up to 10% of E10 fuel is renewable ethanol.
But Does E10 Fuel Damage Engines?
Although most petrol cars can run on E10 fuel perfectly well, a high dosage of ethanol isn’t ideal for most classic cars. Many older cars, and even some modern classics that date back to the noughties, struggle to run on petrol that contains ethanol. This is because ethanol can be more corrosive to components in older fuel systems. Think fibre-glass fuel tanks in some motorbikes and rubbers in some classic car fuel lines.
With the arrival of E10 fuel in mind, classic bike enthusiasts might consider bikes with aluminium fuel tanks in future. And, if you’re unsure whether your fuel lines are made of an ethanol-resistant material, it’s worth changing them.
As a result of these risks, the government has promised we’ll continue to have access to E5 fuel for some time. Look out for ‘super grade’ (97+ octane) fuel in petrol stations.
When to Use Ethanol-Free Fuel
As ethanol mixes with water, this mixture may sit at the bottom of a car’s float chamber and fuel tank if the car isn’t in regular use. Water is a weak acid, so the mixture can corrode and rot a classic car’s fuel system. Therefore, if your car will be sitting unused for a long time, perhaps over winter, it may be a good idea to fill it with ethanol-free fuel e.g Esso Synergy Supreme + 99, which is ethanol-free in most of the UK.
However, if you’ll be using your classic car regularly or on a long journey, E5 fuel should soak up the water in the system, avoiding corrosion problems.
Should You Use E5 or E10 Fuel?
As we move forward, some product manufacturers may need to adapt their automotive formulations to work with E10 fuel. Until this point, it could be a good idea to continue using E5 fuel. Plus, a continuation of demand from classic car owners for E5 fuel should lead manufacturers to continue producing it.
Quick tip: where possible, stick to one type of fuel. If you experience engine problems and you’ve been consistently using a reliable type of fuel, you’ll be able to rule out the fuel as the reason behind the problem.
Is My Car Compatible With E10 Fuel?
You can use the government’s online vehicle checker to know whether your car or motorbike is compatible with E10 fuel. However, the government doesn’t provide specific information on vehicle compatibility for classic cars where the manufacturer isn’t trading anymore. If the online vehicle checker doesn’t list your classic car, you should continue using E5 fuel.
Use the government’s online vehicle checker.
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