coolant is leaking!

I got a 1996.12 Holden Astra seden 2 months ago. When I bought the vehicle, I got to know that the coolant wetness at heater hose block ( from RACQ, Australia). I sent the car to the garage and changed the hoses and clamps. 2 weeks later, I fount the coolant was leaking, maybe several drops a day, then I had to send to the garage again. The mechanist just tighted the clamp and 2 weeks later, it was leaking again, still several drops a day. This time the mechanist removed and replaced the water pipe at rear of motor, then repalced relevant hose clamps ( I am wondering whether this was right). And no leaking only lasts 2 weeks, now it is leaking again! still several drops a day!!!

I am very sick about the mechanist who took me so long time and lots of money but still could not find the real problem. So anybody who can give me some ideas?

Thank you very much!

burn it and buy a ford

sounds like the inside diameter of the rubber hose might be a bit too big, no matter how hard you clamp it, there might be a microscopic fold in the rubber and it will seep, more like weep in this case. should also check the condition of the metal pipe you are attaching the hose to, any small or microscope cracks or lenght wise scratches fluid might leak down?