My AC was not cooling well, so I used a gauge to see if the R134 was ok, it was borderline between charged and low, so I added a 12 oz can of R 134 (without the sealant stuff) on the low side port and it began to make strange noises while my RPMs began to drop. My car died a few times, then the AC worked slightly better but every now and then it starts dying off on me again while making noises. Is my compressor dead??? The noises are like the banging type of noise and the RPMs drop way down when it makes the noise. Any ideas?? It was making the noises a couple of weeks ago before i charged it but they had gone away until now...