Probably either the sending unit or a loose connection.
because the engine in that car does not cool down
The most likely cause is a broken wire or blown fuse.
If the gas gauge stops working is there a fuse for it?
more then likely it could be the temp, sending unit. or a bad wire to temp, sensor!!
Yes.
the sending unit is attached to the fuel pump in the tank.
It is inside of the fuel tank.
$600 for a new pump, sending unit and labor
Fuse location for temperature gauge for a Malibu
If you want a metric speedometer simply hold the info+return buttons down simultaneously for a few seconds, then you can switch to imperial units and vice versa. The better question is "where was that in the manual?" lol
The fuel sensor in the gas tank is bad.
It could be: Bad sending unit, bad gauge, faulty wiring, corroded connector or a bad ground wire. But that's probably the ONLY things that can cause your particular problem.