After the low pressure switch was replaced the AC cooled like a champ and is still doing fine. In reference to losing refridgerant, when I twisted the valve off, there was an instant pressure release but no significant loss of any refridgerant. The base of the switch has an o ring and the new switch has a new o ring which I believe keeps the freon from escaping. I am not familiar with other switches and don't know if they are different or not. My truck is a 96 with the standard 4 cylinder. I am pretty careful around AC repairs and would recommend bringing your problem to a pro. if you lack familiarity with the needed repair.