I would have to hear the fan squeak to diagnose it. Generally, turn the fan by hand and see where it rubs, or if you can feel it seem to hang up a bit at a certain spot.....sometimes will rub against a wire or something else....

As a practical measure, if empty really means empty........that's not too bad.... It's worse when it says you have gas and you really don't..........
Have you done anything recently to the fuel pump...sometimes when they are put back in, the gas gauge float is off to one side and gives an inaccurate reading.

If the car sat for a while the copper wire on the sender inside the tank might have some corrosion on it.
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I always carry a 3 gallon can of gas for emergencies.
For people who think they will get hit or need something to worry about.....I don't recommend that they carry any gas at all.....not even in their gas tank.-Bob