C5 und Biosprit (E10)?

[MadTom]

Also unter"ohne Umbauten" verstehe ich was anderes .

Auszug aus der Betriebsanleitung der C6 2006

Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area. General Motors recommends that you use
these gasolines if they comply with the specifications
described earlier. However, E85 (85% ethanol) and other
fuels containing more than 10% ethanol must not be used
in vehicles that were not designed for those fuels.
Notice: Your vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage would not be covered under
your warranty.