E10 fuel in older cars, and can you use it?

More importantly then, what does this mean for your car and wallet? Let’s face it, that is why you’re reading this article right?

Fuel economy is expected to reduce by a negligible 1%, is this worth worrying about? probably not otherwise you would be driving a diesel.

It has been noted that cars from 2011 are all compatible with E10 fuel but estimated there are still around 700k vehicles in the UK which are not compatible.

These generally  accept E10, but for older models, considering E10 fuel additives for classic cars might be necessary to prevent the E10 fuel starting problems caused by ethanol’s solvent properties.

If you’re wondering can classic cars run on E10, more attention is indeed required when filling up at the pump. Here are a few things to consider when using E10 fuels for classic cars:

• The increased ethanol ratio means there is a higher concentration of solvents. It makes a really good cleaner, but that creates its own set of problems as it starts cleaning out all the old gunk and sludge deposits it has built up over the years. Blocking carb jets and filters.

• These solvents also can dissolve other substances such as rubber fuel lines and seals. This matters because older cars have been made with different quality materials and are not resistant to ethanol (even those that are particularly well looked after) you will find their rubber fuel lines start dissolving over time due to this increased ethanol content. Not a problem you suddenly want to experience during a long hot drive. 

• Ethanol is corrosive to ferrous metals, those which contain iron such as steel. Fuel pumps, Carburettors and filters can all corrode faster than previously.

• Ethanol also burns at a higher temperature compared to petrol, making the engine run leaner which in extreme cases can cause damage to pistons. This requires attention to adjust the carbs accordingly. Whereas modern vehicles fitted with an ECU will adjust the mixture automatically. 

There is a very simple solution to all of this though, one which will cost you more. It means you have to buy the forecourts premium fuel which will still be available, in most cases it’s the 97+ octane, also known as their ‘super’ grade.

Yes, it’s more expensive but it’s a cleaner fuel and it gives you more poke. It’s certainly a better price to pay than experience your carburettors becoming clogged, fuel lines perishing and potentially landing with a bill to repair fire damage.

Yes, that’s right, so if you are wondering if E10 fuel is bad for your car, in extreme circumstances and if you have been using E10 fuel in your classic car for a while, it could potentially completely erode your fuel lines and create a serious fuel leak.

Most of these issues will not be caused by one tank of fuel, but continued usage probably will, if you are in doubt because you have used the wrong fuel, you can always top it back up and dilute it with the 97+ octane.

Will E10 affect performance?

If the vehicle is incompatible then it can depend on how much fuel has been put in, as well as the type of vehicle.

Whilst there is no evidence E10 will affect the combustion directly, the added ethanol will lean out the fuel mixture, therefore the strength of the octane can become slightly weaker.

Petrol standard requirements state this volatility in the fuel needs to remain the same, despite what the mixture is.

It can cause pre detonation, If that is the case then you should speak to your local classic car specialist.