When you got New Radiator, did you checked water flow ?
if not then it might have blocked Pipes (Naliyaan)
so get serviced your Radiator
Mechanic will use a metallic rod to open the Pipes of Radiator after that
for reservoir bottle open bottle and clean it, wash it with surf and rinse with water
pour distilled water into radiator (You can have distilled water from Battery wala shop, it is used to pour in battery) or use water
collected from AC vent and use any appropriate coolant (Caltex, Toyota, Liqui moly, Zic)