Because the temp gauge is not giving you the temperature of the water/steam in the radiator.
You may have a bad head gasket or a cracked head causing the coolant to have that boiling effect.
Depending how high the temperature is going- maybe normal engine is working harder climbing hills Does it stay in the Normal range on gauge?
yes... because you gonna loose water..
low coolant and/or radiator leak or maby a bad temp sensor low coolant and/or radiator leak or maby a bad temp sensor
You say it's running hot, so i am assuming you have hot water in the radiator. If the thermostat was not opening, there would be no hot water in the radiator. Since the temperature sensor is on the engine, it reads the temp of the water in the engine. (Not in the radiator). The fact you have over heating tells me the water is getting hot but the sensor is not reflecting that. I would say it's either the sensor, or the gauge.
Several solutions: Change the thermostat (could be sticking shut).....backflush your radiator....could be dirty and clogged, replace radiator hoses, check for pin hole leaks in your radiator. Is the fluid level staying normal or are you constantly adding anti-freeze? Halfway on the scale is normal.
check your water pump..it might be bad it could be your water pump, or it might be a leak in your radiator. check those first. If the water is green or orange, it is probably coolant, check water pump seal, radiator, radiator hoses, and maybe the heater core. If the water is clear and comes out when the A/C is on, it's condensation from the air conditioning. A/C condensation is perfectly normal.
If I needed to go somewhere, I would risk driving short distances with a faulty temperature gauge . I would keep the radiator filled to the proper level and carry coolant with me. Engines rarely overheat unless a hose breaks or the water pump fails. You can usually tell from the steam that the radiator is boiling before it harms your engine. If your car is old , the weather is very hot or you are traveling in remote areas, the risk is greater. I would get the gauge fixed as soon as is practicable or trade the car.
If you have a "Leak" from the cap either the cap needs to be replaced or the top of the Radiator is damaged. It is normal for thermal expansion (water gets bigger when hot) to cause the coolant to go into the expansion tank when cars is hot and to be drawn back into the radiator as the engine cools
No, a blocked thermostat would not force water out of the radiator. A blocked thermostat would prevent the proper flow of coolant through the engine, leading to overheating and potential damage to the engine. Water may overflow from the radiator due to other issues like a malfunctioning radiator cap or pressure buildup.
Because that's the way it is.
If the temp gauge reads normal and the engine is not overheating, the thermostat is doing its job. The thermostat maintains the coolant temp by opening and closing allowing the coolant to flow or not to flow. When it is closed the coolant doesn't circulate.
Well I have never heard of a water pump warnign indicator but if that is the case, I would say yoru water pump is going or has gone out. Take the cap off a COLD radiator and start the car up and let it idle. When your car reaches NORMAL operating temp see if there is any water flowing or moving in the radiator. Just peer in the hole and see if there is any movement. If the temp goes above normal and starts to get hot and no water is moving it's either the thermostat is stuck or your water pump is out. Don't keep driving the engien hot otherwise you will blow a head gasket or worse.