You can drive it like that but don't smoke near it. On a lot of cars the fuel pump and / or sending unit are mounted through holes in the tank that may be on the side instead of on top. There's a rubber seal that gets clamped in there to keep the fuel from leaking out. There are a number of reason that seal might not seal perfectly. That includes rust on the tank, the lock ring isn't fully seated, or the seal is cut or deteriorated. Most of the time simply removing the lock ring and reseating the seal takes care of it. Try to return to the mechanic who did the previous work. He deserves the chance to correct his mistake or see what else might be wrong.
There is also a rubber seal the filler tube goes through that could be not seated properly.
Be aware too that with steal gas tanks, rust can develop and the resulting pinhole leaks don't show up until the tank is removed and that rust is disturbed. In that case the mechanic only hastened the leak that was about to develop anyway. The fix for that is a new gas tank. That would not be my first suspect because your car isn't old enough to have a rusty tank. Also, most tanks today are made pf plastic.
Tuesday, January 6th, 2015 AT 4:27 PM