My car has 157k on it and the coolant light came on today flashing I looked at the resivoir and it was empty filled it up and then later on that day it was empty again I looked at the bottom of the resivoir and the sensor seems old could it be that? The raditor is fine and so are the hoses there was a little antifreeze from where the senor is
If the coolant level sensor or the coolant tank is leaking then it will have to be replaced. Have you looked right below the upper radiator hose on the plastic radiator tank they crack and leak coolant there very common. Also another common place to leak coolant is the water pump. Also dont over look the coolant cap not holding pressure and losing coolant that way. Let me know what you find.