Ford 1997 Aerostar Manual page 261

Fuel filler door override handle
Removing the fuel cap
The proper instructions for removing the fuel
cap are as follows:
Unscrew the fuel cap by exerting pressure on
the plastic lock bar and rotating the fuel cap
counterclockwise.
Turn the fuel cap 1/2 to 3/4 of a turn until a
hissing sound is heard. When the hissing
sound stops, continue rotating
counterclockwise to remove the fuel cap.
Make sure that you follow the above fuel cap
removal instructions and use caution. Such
caution will minimize the possibility of fuel
spraying during removal of the fuel cap.
To replace and secure the fuel cap, place it in
position and rotate it clockwise until it clicks
(ratchets). Doing so will not damage or break
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