Cadillac Repair: 2001 Cadillac Deville gas guage and fan, cadillac deville, 2001 cadillac deville

Question
I have a 2001 Cadillac Deville. I recently started developing 2 problems. The first problem occurs when the gas level gets below 1/2 tank. The gas gage starts to read as if it is filling up again while I am driving. The second problem is that I am getting readings of my car over-heating. When it says the coolant is hot or the engine is hot, it also gives me a message to turn my A/C off, eventhough it is not turned on. I checked the overflow and it is full. When I checked the overflow there is a build-up of air pressure that is relieved. After this pressure is relieved, it seems ok. When the car "said" it is over-heating, I stopped and the fan was not running. But after I relieved the pressure from the over-flow and finished driving home, the fan was running after I turned the car off.

Is there a sensor that could be causing the 2 problems?  


Thank You

Answer
The fuel problem is caused by a faulty FUEL SENDING UNIT in the gas tank that has to be replaced.

IS or HAS the CHECK ENGINE light ever illuminated on the dash while driving the vehicle ?.

Check the fan as it should come on at approx 220 to 240 degrees of engine temp.