Coolant leakage...from...?

[Tx Firefighter]

They are called freeze plugs, but that is a misnomer. They are more properly known as core plugs. They are not there for freeze protection. They are there because of the necessity of cleaning all of the sand out of the block casting when its made originally.

Here's the straight story.....

http://en.wikipedia.org/wiki/Core_plug

And, the plugs in your block are 1 5/8 inch size. Available at parts stores for a dollar or so. If you had rusty coolant, you have rusty everything. The core plugs are much thinner than the block and will rust out when subjected to rusty coolant for a while. That's why running straight water in an engine is so harmful to it.