Is ethanol or methanol harmful to engine components?
A4. No, one of the provisions of the 1990 Clean Air Act Amendment was that the federal government mandated that by January 1st, 1995, all gasoline in our most polluted cities, must contain 10% alcohol (ethanol or methanol) which will help them run cleaner. The soft parts or the rubber and plastic materials found in gaskets and seals, are susceptible to swelling when individual chemical components by themselves or in large concentrations soak these materials for extended periods of time. However at the dilutions found in fuel system cleaning products (0.1 to 0.4%), they would be in smaller concentrations and can expect to be no more harmful to the rubbers and plastics found in gaskets and seals, than gasoline itself.
