My A/C was low about a month and a half ago. I had my mechanic fill it. He could not find any leaks. About a week later it was blowing hot. I pressure checked it and it did not have anything left. I filled it with some that had a leak sealer. It has worked great since. It started to blow hot on Friday I checked the level it was still in the green so I filled it to yellow. Nice and cold until this morning Tuesday now it is cool but not cold. Do not see any leaks.