Bruce, I misunderstood your original posting. I thought you said that Rich was suggesting to coat the head gasket w/radiator sealant, which didn't make sense to me. As the old saying goes, sometimes I can't see the forest for the trees.
Burner31, I remember the 50's also, I was just a snot-nosed teenager then growing up in a small town, but I never heard of "mechanic in a can" either then or since until now. But then again, I'm in Canada and I suspect there was a lot of expressions or slang terms that never migrated to Canada from the US.
We all speak "english" but there is sure a lot of variations from country to country around the world.