The radiator in any vehicles, its fluid temperature reach above 100? Why the fluid not evaporating?

Water has a boiling point of 100°C and evaporates at temperatures above this. Coolants, which are mixture of glycol and water, rather than just water, are instead used in engine radiators. This mixture has a higher boiling and lower freezing point than water. But keep in mind that the radiator works in a pressurised system and as such the coolant inside have an even elevated boiling point. More over the radiator fan does a good job in keep the engine temperature in a controlled range. Considering the high specific heat and great thermal conductivity that coolants offer, heat is released as soon as gained to prevent vapourisation.