Yesterday i got my cultus complete engine overhaul, the car engine seems built good

anyway the problem is when the car was on normal temprature and radiotor cap was already open, i just turn off and turn on the switch and radioator throu the water, just like issue on gasket. mechanic said to me its because radiator is chocked.. i got radiator service but again when car was on normal temprature it agian through the water? I saw car was not developing pressure neither bubbles were seen. my cultus has also installed thermostat valve and its in working condition. now mechanic says it's nothing just because thermostat valve is installed? that's all happen in front of mechanic that car was throwing water when it's on normal temperature....

brothers! plz suggest me what could be the issue? I have already spend lot of money on engine overhaul....