Q: Is it the 1/2 " overflow pipe that runs along the top of the rad and meets a T junction, one going back to the rad and the other around behind the engine , below Inlet manifold , beside the oil dip stick. Have tried to use punch, but no movement? Any other suggestions?
A: check for any air valves on the coolant system/pipework....if air is in the system it will over heat....start car,warm up,and loosen one at a time tillonly water comes out then top up rad.