any cars radiator pipes will be hard when normal operating temperature is reached, this pressure is also mentioned on the radiator cap, If the pressure is exceeded then you will see the expansion tank constantly boiling over. If its not boiling or bubbling over then everything is normal.
The old mechanics who think that the radiator pipes should be soft are ill informed, they should only be soft after cold start, the will become hard due to pressure build up at temperature.
If your pipes are expanding (swollen) and become larger than original size you need to replace them because their nylon reinforcement is broken inside.