Why are they called that?

[Bill I.]

There is a post on currently that asks about freeze plugs.
I know what they look like, but why are they called that? Bill.

[Mike M.]

Re: Why are they called that?

in the event your engine's coolant reached the freezing point, before the cast iron block cracked, the freeze plugs were intended to pop out and hopefully the frozen coolant would expand thru the freeze plug hole and prevent the block from freezing. in extremely low temps, the plug would pop and the block could still crack. mike

[Bill I.]

Re: Why are they called that?

Thanks Mike, I have been learned. Bill

[Loren L.]

Re: Why are they called that?

Don't know where Bill was born and raised - but I do KNOW it wasn't northern North Dakota......

[Erv M.]

Re: Why are they called that?

We don't have a name for them in California!!

[John H.]

Re: Why are they called that?

The real reason for them is to plug the holes in the sides and ends of the block that are there so the core sand from the inside of the water jackets has a place to exit the raw casting when the sand mold was opened and the block hit the "shake-out" table in the foundry. Most folks aren't familiar with how large castings with internal passages are made, so it became popular to call them "freeze plugs" - that explanation is easier.

Photo below shows a (6-cylinder) block that has just had the mold halves (cope and drag) stripped off, on its way to the "shake-out" table to knock the remaining sand off (and out of) the block before proceeding to the finishing line.

[Duke W.]

Re: Why are they called that?

What John and Dave said....

Maybe laymen call them "freeze plugs" because it's easier to understand, but as some have found out, they rarely protect the block from cracking if it freezes solid although the plugs may pop out, which means the area immediately surrounding the plug may not crack.

Duke

[Dale S.]

Re: Why are they called that?

I've also heard them called "Soft Plugs". I think it was a "Pic-A-Nut" display. Steel and brass as I remember. Dale

[Karl L.]

Re: Why are they called that?

DAVE AND JOHN..... "VERY INTERESTING"

Karl.

I guess we have all heard the terms...Soft Plugs..Freeze Plugs, Etc. before.
Some times they popped and other times the block just cracked and the plugs stayed intact.

Years ago, before the Antifreeze as we know it now was used, a mixture of Water and Alcohol was used. The evaporation of the alcohol in the system caused many cracked blocks if not checked regularly.
We should be thankful for the improvements over the years.

Karl.

[Michael B.]

Re: Why are they called that?

I guess we have all heard the terms...Soft Plugs..Freeze Plugs, Etc. before.


Don't forget Welch or Welch Expansion Plug.

[Karl L.]

Re: Why are they called that?

Never have heard the term..."Welch or Welch Expansion Plug."

Maybe a Manufacturers name?

[Edward B.]

Re: Why are they called that?

Try www.britishcarweek.org/welch_plug.html for an explanation of the name.

[Kenneth B.]

Re: Why are they called that?

The real reason for them is to plug the holes in the sides and ends of the block that are there so the core sand from the inside of the water jackets has a place to exit the raw casting when the sand mold was opened and the block hit the "shake-out" table in the foundry. Most folks aren't familiar with how large castings with internal passages are made, so it became popular to call them "freeze plugs" - that explanation is easier.

Photo below shows a (6-cylinder) block that has just had the mold halves (cope and drag) stripped off, on its way to the "shake-out" table to knock the remaining sand off (and out of) the block before proceeding to the finishing line.

JOHN is right on. The core is what makes the internal shape of the casting. Sometimes cast in exit hole that could be used to hold the sand core in place till the metal was poured in to create the internal casting wall were not there as in water jacket cores for heads & blocks. Core prints would hold the core suppended in the proper location. These holes had to be pluged