If the pump is not circulating coolant insure that the thermostat is not stuck closed. If the thermostat is ok then the pump will have to be replaced.
Water pump shaft loose? Water pump leaking? Water circulating in coolant system?
If the engine is warmed up, the thermostat has opened and coolant is circulating, the pump is pumping.
Low coolant? Thermostat not opening? Water pump not circulating coolant?
Low coolant? Cooling fan not working? Thermostat not opening? Water pump not circulating coolant?
Could be a plugged or restricted radiator Low coolant? Water pump not circulating coolant?
Possible causes: Insufficient/no coolant in the system; insufficient antifreeze in the coolant and the coolant is frozen: the water pump is faulty and is not circulating the coolant; the belt that drives the water pump is loose or missing.
To check if a 2002 Jeep Liberty's water pump is circulating water, start the engine and let it reach operating temperature. Open the radiator cap (if safe) and look for movement in the coolant; you should see it circulating. Additionally, feel the upper radiator hose; it should become warm as coolant flows through. If the hose remains cold and you don't see coolant movement, the water pump may not be functioning properly.
You should see the coolant circulating in the radiator when the car is running
Low coolant? Cooling fans not working? Water pump not circulating coolant? Radiator plugged or restricted?
Low coolant? Cooling fan not working? Radiator restricted or plugged? Water pump not circulating coolant? Defective radiator cap? Low coolant? Cooling fan not working? Radiator restricted or plugged? Water pump not circulating coolant? Defective radiator cap?
Is thermostat opening? Is system airbound? Is water pump circulating coolant?
Low coolant? Bad thermostat? Heater core airbound, plugged or restricted? Water pump not circulating coolant?