We recommend all classic drivers to avoid E10 for as long as possible.
All petrol engines create acids as part of the combustion cycle, and the additional impact of E10 is minor. Modern oils do have higher detergency to nullify the effects of the acidity, but are generally not suited to older cars, especially those without oil filters. We expect E10 issues to be limited to people using ‘classic’ monogrades in older (mostly pre-war) vehicles, and our recommendation is to change to one of the Penrite Shelsley range, which are designed for cars of that generation but have chemistry better able to deal with E10 combustion acids. Being an Australian product, it has more history with E10 which was introduced there more than three years ago. https://penriteoil.com.au/products/shelsley-light-20w-60-mineral
We strongly recommend anyone who continues to run monograde oils with E10 fuel to engage with an oil analysis service such as our ‘Insight’ programme, which will identify issues with oil degradation before they become serious.
Hope this helps