Check coolant level Could be thermostat opening and closing due to engine coolant temperature flutuation
Because Science.
Simple weather measurements can be done using a thermometer (temperature), gauge (rainfall or snow), barometers (atmospheric pressure), humidity (water vapour present in the air), weather-vane (indicating wind) and visual observations (cloud amount).
To measure temperature. A gauge can be used instead of a thermometer, and is generally used in industry where a thermometer might be too fragile
thermometer barometer weather vane rain gauge
One of the earliest temperature gauge was published by Giuseppe Biancani and was known as a thermoscope in 1617. Gabriel Fahrenheit was the one who invented the first modern thermometer.
An automobile temperature gauge can fluctuate when the thermostat is opening and closing erratically. The temperature gauge can also fluctuate when the ground wire is loose.
Temperature.
The temperature gauge on a car fluctuates because the car's thermostat is opening and closing. The gauge goes up when the thermostat closes and the gauge goes down when the thermostat opens.
low coolant
A short in the turn signal wiring can cause the voltage gauge to fluctuate. A loose ground wire can also cause the gauge to fluctuate.
Possibly the thermostat is opening and closing with the water pressure changes. Could be low on coolant also.
My Altima had that problem and it was the water pump going out. It started with temperature gauge was moving, but then it started leaking and finally the heater stopped being warm at idle.
Potenially a bad temperature sensor or bad contact on the wire connector. Test for set voltage resistance according to temperature.
is the coolant disapeering at all ?
Because Science.
Could be low on coolant or a sticky thermostat.
Your check gauge light comes on if : your coolant temperature guage shows the temperature is high your oil pressure gauge shows the oil pressure is low or your fuel gauge shows the fuel tank is near empty