we have been having problems with our '01 S60 gas tank. The problem started when the car dumped its gas while going down the road. My wife was driving and she heard a "Clunk" (did not feel anything hit the car. She then noticed she was out of gas. when the service station wen tot fill it up the gas went on the ground instead of into the tank. The dealer replaced the tank and the dump valve (?) However, the gas must be put in very slowly and the gas guage varies between half full and zero. When fueling the the gas must be put in very slowly. The dealer claims to have replaced the tank, yet when I look underneath the car, the tanks (one on each side of the rear seat?) look deformed -like something had pushed the bottom of each tank up. What are these tanks supposed to look like? Should the bottom of the tank be flat or pushed up?