Getting to know your E10s from your E5s important for classic cars

E10 petrol is the new norm at the pumps. E5 where available, is the higher octane fuel that classic cars should use unless modified to prevent the damage ethanol fuel can cause.

E10 has been around for two years and has 10 per cent renewable ethanol, up from the five per cent in E5.

It is designed to be eco-friendly because it burns less fossil fuel with fewer emissions. However, ethanol contains less energy than gasoline so achieves less mpg but this is minimal.

Ethanol is not only corrosive to rubber, plastics and alloys but is also hygroscopic meaning it absorbs and holds water over time. Not good news in any car especially a classic.

Most petrol powered vehicles from the late 1990’s onwards are compatible and there is a Government compatibility checker tool at GOV.UK

The damage to a classic car, as I found to my cost with my 51 years old Triumph TR6, is potentially very serious. I had not been in my garage for some time only to discover fuel residue on the floor and a stench of flammable fuel throughout. The garage is where the house boiler is located and it fires up several times a day!

A rubber fuel pipe under the tank had literally rotted out and allowed the entire contents to leak out. I have yet to discover what other damage has been caused further up the fuel system.

My mistake was to have run out of fuel and I used a spare can of E10 from a supermarket filling station to get me home quite forgetting the consequences.

Leaving E10 in the tank for a short time is not a problem but must be removed as soon as practicable.

Misfuelling with E10 is not like misfuelling with diesel. Simply drain off the incorrect fuel and refill with E5. But much easier is to take a spare can of E5 and drive till all the E10 is used up, then replenish with E5 from the can to get home.

I suggest avoiding the practice of leaving a stored classic full of fuel to minimise water collection.