The fuel system on any car or light truck that has been manufactured since the 1980s should be compatable with gasoline/ethanol mixtures of up to 10 percent ethanol. However, ONLY vehicles that are built to be FLEX FUEL vehicles can handle higher blends of ethanol alcohol (E85).
Alcohol is a strong solvent and may cause noncompatable plastics to soften or swell. It will also loosen and remove accumulated varnish from the fuel system, which may cause fuel filter clogging if the system is dirty and has never had any alcohol or fuel system cleaner run through it.
Technical Editor, Counterman magazine