2001 318i e46 coolent level drop

My car is leaking coolent between the thermostat and the pipe from there to the radiator. I have replaced both the pipe and thermostat but it still leaks. I opened the pipe from the radiator to the cylinder head and it now leaks from there as well, The pipes are fitted correctly and clamped in properly. Please help, what could be causing it to leak. What can cause the build up of pressure. The car moves great and no smoke,or overheating or excessive water out the exhaust or mixing of oil and water.