Chevrolet 2009 Aveo Owner's Manual page 217

Hatchback shown. Sedan similar
The tethered fuel cap is located behind a hinged fuel
door on the passenger side of the vehicle.
To remove the fuel cap, turn it slowly counterclockwise.
The fuel cap has a spring in it; if the cap is released
too soon, it will spring back to the right.
CAUTION:
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Fuel can spray out on you if you open the fuel cap
too quickly. If you spill fuel and then something
ignites it, you could be badly burned. This spray
can happen if the tank is nearly full, and is more
likely in hot weather. Open the fuel cap slowly and
wait for any hiss noise to stop. Then unscrew the
cap all the way.
Be careful not to spill fuel. Do not top off or overfill the
tank and wait a few seconds after you have finished
pumping before removing the nozzle. Clean fuel
from painted surfaces as soon as possible. See
Washing Your Vehicle on page 5-82.
5-9