cooling fans or plugged radiator or hoses.
99 Cadillac deville over heats no circulation from reserve
The thermo fan sensor is on the thermostat housing, right below the distributer.
if your car over heats alot then that is a pretty good sign. aslong as it isn't your water pump. but thermostat is a good place to start. if you replace the thermostat and it still over heats. (assuming that is why you are asking) then it could be the water pump.
There could be several problems including a faulty thermostat, low coolant, a bad water pump, or an operable radiator, or leaky hoses. Narrow these down and you should be able to find the problem.
Water pump malfunctioning. Thermostat stuck closed or partially closed. Radiator plugged with sediement.
did u check the antifreeze/coolant level because my 91 fleetwood was doin the same thing i filled it up and now the heats comin out real good
low or no coolant, or a bad thermostat.
it heats up the thermo couple which opens up the gas control valve allowing gas to flow to the main burner. if the pilot goes out the thrmo couple will cool and shut the gas valve so gas does not come out
it might be the belt
The fuel could be damaged and could melt if temperatures get high enough
It heats from the celci-di that heats an outdoors calborithm
Check your fan to see if it is turning good with force when hot, you may need to replace the clutch fan.