Is it smoking a lot? If so you probably have a blown gasket. If it's not smoking, check the thermostat. I don't get how a car could be not getting hot but using a lot of water and the temp gauge is going up. Have you checked for leaks?
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.
mostly likely something wrong with the sensor or gauge.
could be a number of things, more than likely the sensor, the wiring or the gauge itself, i'd take it to a garage then you can blame them if it goes wrong :P
add water to the radiator. believe that. if there is no water flowing through the engine, your heater will only blow cold air. if there is no water flowing through the engine and your heater is only blowing cold air, and not HEATING, your heater core is probably going out or will be soon. most people believe that if you have no water in the engine then your temperature gauge will run hot and you will know that you are overheating the engine. WRONG! your temp gauge only measures WATER temp. But if there is no water to measure, there is no temperature rise showing on the dashboard gauge. if you have NO WATER in the engine you can seriously overheat your engine and not know it because the gauge is not getting any hotter than usual (sometimes your gauge will even read cooler than usual).
If you are absolutely sure you do not have air trapped in your cooling system then you may have a defective gauge if you are getting heat through your heater. Usually I would say you have a coolant flow problem with either a stuck thermostat or a bad water pump but if you have heat from your heater, then you must have circulating coolant in your system. I would check the gauge or the sensor.
Could be temperature sensor Could be gauge
No - the gauge reports 'real-time' the engine temperature. If it is wrong, there is a problem with the sending unit on the engine. This is a pretty easy fix...
Mine was a bad ground on the gauge. Easy check by any certified mechanic.
If the outside temperature gauge is not reading the right temperature on a Buick Regal, perhaps it has become damaged. It can also not read the right temperature if it is wet or covered with dirt or snow.
could be the temperature sending unit
Either the thermostat is not working properly or the temperature sensor is displaying wrong on your gauge.
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