1999 Nissan Quest Van overheats

My 1999 Nissan Quest was overheating so i took it to the mechanics and he said i need a new Radiator and Thermostat , so he replaced them both . 2 days later its still overheating so i took it back , he said you need a new water pump along with timing belt so he replaced them both then the next day its still overheating so i took it back and he said he had to replace the Thermostat Unit so he did , now 4 days later ! This morning i turn it on and there is a loud clicking sound but as soon as i drove away the sound is gone but i get on the freeway and it starts overheating again !! Does anyone know what it could be ? Thank you