Because the water box(水箱), follow the car's engine temperature and outside temperature to grade, The most way to prevent the water box over-heated, don't acclerate your car when you're in P and N gear( if in Manual Transmission dont stay in N gear acclerate+ dont acclerate too long in each gear!!)
** All over-heated problems are from the Manual Transmission Cars, because some of the drivers dont change gear, and take the engine to the highest temperature.
REMEMBER!!!! DONT OPEN THE ENGINE AND WATER BOX WHEN OVER-HEAT!!**