Need to know the year and engine size.
only 3 reasons a temp gauge wont work the temp sender is bad the gauge is bad or the wire from temp sender to gauge is broken
check the temp sending unite on the water intake
Your car engine isn't getting up to the desired temperature, about 130 degrees Fahrenheit.
why doesn't my rpm gauge and temp gauge, fuel gauge not work
THE temp sending unit 4 the inside gauge usally has 1 wire & the sending unit 4 the Computer has 2 wires.
operates the temperature gauge Activates the cooling fan
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.
see this http://users.sisna.com/ignatius/subaru/headgasket.html
A good sign of a water pump going bad is noise. It usually makes a grinding sound. Another sign is antifreeze leakage around the water pump. Some manufacturers put a small hole on the top side of the pump so that when the bearings fail coolant leaks out from this hole. Another good sign is high water temp gauge. When the water pump goes bad it fails to do its job of pumping coolant through the engine, hence the high water temp gauge. Hope this helps.
i have seen them on the intake, head, and thermostat housing also on the block in front
1996 prelude temperature gauge reads low temp
temp gauge is stuck on hot