They are not frozen prior to installation. They are stamped metal (either brass or steel) and have a
slight outward taper on the sides. They are driven in and the taper retains them.

These plugs are commonly referred to as freeze plugs because they will pop out if the coolant freezes.
This however is not their purpose. They are actually core hole plugs and they seal the holes left when
the core supports are removed after the casting process. The core is used to to form the internal
passages in the block and is removed during the shake out after the casting cools.

Gene Kearns wrote:

On Tue, 13 Apr 2004 00:25:33 GMT, "Calif Bill"
wrote:


"Douglas St. Clair" wrote in message
. ..
I have a 427 Crusader in a 1970 Century Resorter. Over the last two
winters
two 1 3/4" brass plugs have popped out from under the engine block and
were
found sitting in the bilge. Last year I simply pushed them back into
place
and the boat ran fine.

Are these so-called "freeze plugs"? Both winters the boat's been
winterized
as usual. Should I be concerned about these plugs popping out? Should I
do
something to secure them in place so they won't pop out while the boat is
running?

Thanks!



Yes, they are "Freeze Plugs". Named because they froze them to install, not
because they protect the block when water freezes. Go to a good auto parts
store and buy a couple of new plugs. They are not reusable. They will run
you a buck or two each. Then you drive them into the hole. Add a small
amout of Permatex sealant on the edges before driving.
Bill


Assuming your specious explanation is so..... should he freeze them
first?

--

Grady-White Gulfstream, out of Southport, NC.

http://myworkshop.idleplay.net/cavern/ Homepage
http://www.southharbourvillageinn.com/directions.asp Where Southport,NC is located.
http://www.southharbourvillageinn.linksysnet.com Real Time Pictures at My Marina
http://www.thebayguide.com/rec.boats Rec.boats at Lee Yeaton's Bayguide