So my car is still over heating after replacing the radiator and thermostat, it was fine for about 4 days then started heating up again, my uncle said it is likely the water pump but it could also be because the timing is off.. is that accurate?
Those are possible reasons. Is there/was there any oil in the coolant or milkyness to the oil? You could have a blown head gasket or warped head. A compression check would help eliminate those possibilities.
Is the water in the expansion tank boiling?
If it is then you can have a head gasket blow, but it allows the crankshaft gas to pressurise the cooling rather than leaking oil in to the water or vice versa