*MUST READ*--Flex Fan Danger--Be very careful working on old cars

I wonder how much harmonics play in them exploding.
Loose water pump bearing, fan spacer etc.

Personally I think it has a lot to do with it, because I have heard popping noises before from the water pump area with an engine running and found out it was a crack in the fan hub.
I figure if it was popping because it's moving around so it must be doing something to make it move around.