Recharge the coolant or replace faulty thermostat.
If you mean "How does the inside temperature increase and stay there when you turn up the temperature" it's because there is a thermostat inside the oven. When you set the temperature on the oven, the heat will keep increasing and would keep going higher and higher if it wasn't for the fact that there was a thermostat inside. The thermostat will 'click off" once the temperature inside the oven has reached the temperature that you set the dial at. Basically, the element will turn off once it has reached this temperature, and will turn on again when it has cooled the oven down by just a few degrees, then the heat will increase again until it has reached the set heat-level again etc, and so on and so forth. The temperature the hottest to the coolest as this goes on.
What you are probably hearing is the fan. On the thermostat control, there is the fan control. It has two settings, on and auto. If it is on, it blows all the time. If it is on auto, it will continue for a while after the outside unit shuts off but should shut off shortly afterward. It is usually set to shut off depending on the temperature of the inside coils. (On the other hand you may have a more modern thermostat which keeps the fan going all the time and turns the outside unit on and off frequently.)
Your car is starting to overheat or your thermostat is going out. Get it checked.
Any Auto Parts store can tell you the correct temperature thermostat for your Impala. Probably it requires a 195 degree thermostat. One thing for sure is no thermostat is not what you want. Running without a thermostat, will cause the engine to not reach full operating temperature. The engine will not perform to peak efficiency at below normal operating temperature. Normally that is around 220-230 Degrees. Your engine is computer controlled and the computer bases fuel/air mixture and timing on the engine temperature. Install the correct thermostat.
It is inside the thermostat housing which is on the engine side of the big hose going to the top of the radiator. Pull the housing off with 2 bolts and the thermostat is inside it. Make sure you point the spring of the new stat towards the engine.
It could be a number of things, but my first guess would be a faulty thermostat.
The temperature sensor should be located close to the thermostat and has one wire going to it.
Could be low on coolant or a sticky thermostat.
To find the thermostat, first find the upper radiator hose going from the radiator to the engine. It's a big 3 inch hose. Where the hose connects to the engine is where the thermostat is at. It's called the water outlet housing. The housing contains the thermostat, 2 sensors and the hose going to the heater. Take this housing off and the thermostat is located inside of the housing. When replacing the thermostat make sure the tabs on the new stat fit inside the slots on the housing. The spring of a new thermostate always goes towards the engine.
The thermostat is located facing the engine bay on the right back side of the motor, it looks like a shiny metal knob with a hose going into it. That's the housing, the thermostat is inside that
The thermostat is on the input radiator line going to the engine. Take the line off on the engine and the thermostat should be there. Now if you are talking about the thermostat for inside the car and not for the engine, the correct term for it is the climate control thermostat and it is located behind the wheel below the instrument cluster where there is a vented inclosure.
More information is needed before this question can be answered. Is that "temperature"? Are you talking about the temperature gauge? And what is it on? A car? A refrigerator or freezer? The thermostat? The world outside?