There is a valve on the back of the compressor. If your high side head pressure is too high, a check valve opens to relieve the pressure into the atmosphere. It is almost imposible for a compressor to blow or leak freon from the back side. If there was a large rush of freon and a very noisy strange sound, then it was probably your pressure valve. Usualy a compressor that fails will leak freon from the front clutch seal or just plain seize up. Before you condemn the compressor you will need to find the leak. Generaly the relief valve tripping is due to an incorrect freon charge, blocked/dirty condensor, or malfunctioning condensor cooling fan. Save yourself some money and do some further troubleshooting first. Hope this helps.
