no you need to replace temperature sinding unit
Leak. What kind of liquid should be coming out? Antifreeze? Oil? And would it make the overflow for the raditor liquid bubble?
First thing would be to check if you have enough and correct water/Antifreeze mix in the overflow tank.
The system was overfilled and purged the excess coolant.
If there is no leak visible so you can see antifreeze under the parked car, you probably have a head gasket going bad. You may have some signs of steam in your exhaust, or at least a sweet smell coming from the exhaust. You should have a compression test done on your engine. That is exactly what the overflow reservoir is for. When the engine is hot, excess coolant goes into the overflow tank, as the engine cools,it draws coolant back into the radiator.
It is important to keep fluids from leaking from a car. Excessive transmission fluid would be coming out of the overflow because there is too much fluid in the transmission, or because the seal has become worn.
your Toyota should have an overflow bottle to retain the antifreeze during normal operations. Unless it is overfull, I would be looking for a leak.
Probably - your head gasket is blown. Antifreeze will be coming out of the tail (exhaust) pipe.
Probably need to add antifreeze. Check the Radiator not the overflow tank. If you are low on antifreeze it will not circulate through the heater core.
I would say you have a bad water pump, thermostat or a bad hose depending on where the antifreeze is spraying from. If the antifreeze is coming from the timing cover area you have a bad pump, if it is coming from the front area of the motor I would say bad hose, if you are hearing a gurgling sound from the radiater I would say bad thermostat.
I'm guessing that it has a closed radiator, so one would use the overflow basin to add liquids. Otherwise one would use the radiator cap..
internal engine leak is possible, smell your exhaust is it sweet? is there moisture coming out of your tail pipe? is there water in your oil? it is also possible for your engine to run so hot that coolant evaporates as steam through the overflow tube into the fill tank, keep it full
check antifreeze level