I was also losing coolant, very little , but it added up over time, never saw any dripping......But early one morning, as I was standing away from my car I noticed a tiny drip from behind my flywheel, apparently a freeze plug, I added some stop leak, and it stoped, some of that silver stuff in the round container, kinda like flakes, used 2 containers, never leaked again. cross finger, knock on a old 240 fender.......
Charles
Charles