problems on 91 3.3l with 273,000 miles....

i havea 91 3.3l with 273,000 miles.. couple problems one.. the fan makes a real loud noise everytime i turn it on so i have no heat now, this just happened with in the fast few days... next my needle drasticly floats when the car is running the needle will be off from when its parked and turned off. ie half tank parked 1/4 tank when driving
also i have a leak in the gas tank im pretty sure.. you can really smell the fumes when i fill it over a 1/2 tank but i never notice any gas on the ground how much do these run?
thanks alot
jon

273,000 miles huh. Be glad it still is drivable!