The chemicals in ARX are supposed to clean any gunk around the seal and soften it during the clean cycle. Then during the rinse cycle the seal material firms up again. This softening and firming up process is supposed to help reduce leakage from seals. Of course if the seal is too far gone it will not help. There is some interesting reading about this product on their web site. Even more interesting is the reading of the patent for the product on the US patent office web site. They describe how it was shown that this product works. (actual engine teardowns)