I have a 230SL 5 speed with a 250SE engine. I've been running whatever fuel I could get for the past 25 years and really never have any problems with ethanol. I've had to replace the hose coming right off of the fuel pump once or twice in all those years but I think that has more to with it being rubber impregnated cotton ( or something like that ) than anything else. We use 10% ethanol blend here. Premium is supposed to be ethanol free.


I would adjust your valves to .003 and .007 and use a high zinc content oil. Blends used for diesels seem to work well. Burned valves and heavily worn cam shafts are often due to a lack of valve adjusting. You will always hear a loose valve rocker but you will never hear a tight one.