1997 Acura TL reverse water problem

Hi, I have 97 acura tl 3.2 my radiator los t some water while my reverse tank full of water. My mechanic already changed a new radiator, fan relay, fan switch( while the fan still work good). It still continue lost water from radiator and full on the reverse water tank. He told me to change a cap for three time and themostac for two time with difference kind and bleed air too. However, the water still continue lost and full on the reverse tank. The mechanic states the water has to be go forth and back between the radiator and reverse tank. Righ now the water not go back to my radiator, please help me to solve this problem, thank