As stated above, it is common for the filler neck to rust through on "rust belt" cars. Dirt and debris collect under the corrugated plastic cover, trapping moisture and the cancer follows:
This is from a Northern friend's car:
Removing the plastic condom and spraying the tube with a anti-rust product like LocTite Extend
may catch it in time.
My '03 has been and will be a Florida
car for its whole life but I still removed the cover and shoot it with Extend once a year or so...
- 2003 GT, UPR X, FRPP 24lb/h, Magnaflow, PP 70mm TB & plenum, Delta Force tuned,
Steeda UDPs, Ralco flywheel, RAM HDX clutch, 3.73s, 262 rwHP/305 lb-ft.
New ride (7/1/2013) 1998 Mercedes SL500-5.0L 32V VVT 326/347 HP/tq