[Simple Man]

Originally Posted by Fullsize455

That's because they aren't freeze plugs, they are core plugs for evacuating sand out of the block during the casting process. They have nothing to do with freezing, despite the myth that has been perpetuated for decades.

https://en.m.wikipedia.org/wiki/Core_plug

Correct, but they are made out of thin metal, instead of heavy cast iron, so they usually go first.