Greetings,
Mr. C. Yep. It was about time. Mr. SK. My WAG is expansion and contraction of the cast iron with water finding it's way into the body of the casting. Rust causes expansion and extension of any cracks.
yes it was preventative maintenance. This is the start of our third season. Got no maintenance records at all. Also just got done replacing all the hoses on the engine. What a chore.