The Stovebolt Site Forums The Shop Area Engine Shop How do you put freeze plugs in?

I disagree on the sealant keeping the freeze plug from popping out if a freeze-up were to happen. It's the path of least resistance. Ice formation has the feature of the last spot to freeze is the one that breaks due to the ice around it preventing the expansion (water to ice) from releasing. So if the freeze plug freezes first, the block is going to crack anyway.
That being said, "freeze plugs" are actually core holes for casting the block, and freeze protection is secondary to being able to get the core positioned for casting and the sand out after casting. The plugs primary function is to keep coolant from leaking out of the core holes.
I say seal them up. They're more likely to leak because of corrosion that fail to pop out if a freeze-up happens.