Is the radiator fan coming on or not at all?is the thermostat installed in the right direction?Is the water pump leaking through the drain whole or is it a weak water pump?Is the gage showing " overheat right away after you start the car?Is it overheats only when you turn the air condioning on?Is it air pocket in the cooling system after you fill it up with coolant?
give me some answers and I will be back to you as soon as possible.
Mechanic On Wheels LLC