E10 petrol: How it affects your Mini
The make-up of the petrol that we put in our tanks has changed over time and, from 1 September 2021, it is to change again in the UK. The previous two major changes have been the removal of Tetra Ethyl Lead (TEL), in the later 1990s, and the introduction of up to 5% ethanol in 2011. Now the percentage of ethanol is to be increased in regular unleaded petrol to up to 10% and it is to be known as E10. (It is called gasohol in some other markets).
In reality this means that E10 petrol may contain between 5.5-10% ethanol by volume and the changes have been made by the UK Government for environmental reasons. There are arguments for and against the environmental benefits of ethanol in petrol, and better alternatives, but here we are looking at how ethanol affects the fuel system and running of all Minis and, indeed, virtually all petrol-engine cars made up to the year 2000,
