sounds like water pump.check radiator hoses as well
A leaking heater core will cause the engine to overheat because the coolant is leaking out.
No, low coolant would cause the opposite.
No.
Leaking injector is the most common cause.
heater core leaking
head gasket is leaking into oil
Heater Core
If by water you mean engine coolant, yes. Loss of coolant, antifreeze, is a major cause of overheating.
If it is leaking trans fluid into the coolant it can cause overheating.
gasket wears out in time. leaking coolant is the result of a bad gasket not the cause of it.
A bad or incorrect radiator cap.
Intake manifold gasket