Hi Gang, First, yes Mike it is made up of HCFC's. And you should fix all the leaks anyway. Otherwise you will lose Freon and oil and without replacing the oil, you will run the system short. As I said, I haven't tried the stuff yet but I understand your thought on the different leak out rates but remember R134 will leak out through most old hoses unless they are the barrier type hose which stops seepage through the rubber. Second, I have talked to Lowell Howe about revulcanizing motor mounts. He has a shop that can make the mold and redo them but he was thinking of making a whole new mount. I thought that if we all got together our cores and gave them to him all at once the price could be kept down and we could all wind up with spares as well as needed ones. Anybody have any thoughts on this ? If you want, you can let me know if you have cores you want done and I will keep a list. When we get a total amount , we can then find out a price and see what happens. Let me know at BANDMGRINDING@xxxxxxxx Thanks Allan R 62 vert 63 vert