Posted by Gordon on Saturday, February 01, 2003 at 6:22AM :
In Reply to: Re: You mean Frost Plugs ? posted by Tom J. on Saturday, February 01, 2003 at 0:56AM :
These are the holes that the ends of the sand cores come through. The cores form the water jacket and internal structure of the block and they sometimes don't get cleaned out as well as they might do, so don't worry if you pull a core plug one of these days and find sand behind it.
Gordon