Freeze Plugs aren't there to protect from freezing!

[Don S]

Was reading a previous thread and thought it might be a good idea to post what a freeze plug really is.
First of all, they have been called Welch plugs, Freeze plugs, and a few names I can't print here.
They are actually CORE plugs. They were designed to Hold the core in place for the water jackets during the casting process. That's all. Then they came up with these plugs that sometimes fall out when the water in the block freezes and the slang word started. Have no idea when that stared either, so don't ask.
After the casting is cast, it's also a great way to get all the core material out of the water jacket.
So if you expect a CORE plug to protect your engine from freeze damage. You are in for a real expensive surprise.

As suggested by DHP, here is the Merc Service bulletin 87-14 which also explains the Core Plugs and freeze damage as well.

Service Bulletin Link

 

[Limited-Time]

Re: Freeze Plugs aren't there to protect from freezing!

Glad you posted that Don. Saved me a lot of typing BTW ya may want to add the H to the word hold...........gott'a love the edit feature

 

[RCSConstruction]

Re: Freeze Plugs aren't there to protect from freezing!

haha Don. I think you must have caught my post.
I tell ya what, southern California boys don't know much about freezing weather.
I would have bet the farm they were for expansion of frozen water.
Thanks for the info.

 

[Don S]

Re: Freeze Plugs aren't there to protect from freezing!

Your post was just the final straw. Explaining them happens all the time. I just figured it was time to post something that someone might find if the do a search.

PS Limited time..... I fixed my typing error. Ya know what is really funny. When in school many years ago, some one said I should take typing. I said why, I ain't gonna be a secretary (Circa early 60's).......... guess I should have listened.

 

[SuperNova]

Re: Freeze Plugs aren't there to protect from freezing!

While we're here we may as well correct Limited-Times signature--you need to swap the "s" and the "e" in "dose".

 

[Boomyal]

Re: Freeze Plugs aren't there to protect from freezing!

Don, undoubtedly you are correct, howsomever on two occassions I have been lucky with ford 302's. They popped the "plugs' out instead of breaking the block. On the third occassion, however............., well, you know the rest of the story.

 

[Don S]

Re: Freeze Plugs aren't there to protect from freezing!

Some times they do pop first. But they weren't Designed for that purpose. That is what I am trying to explain.
Sometimes it's just better to be lucky and not try to expain it.

 

[DHPMARINE]

Re: Freeze Plugs aren't there to protect from freezing!

Don,I have yet to learn how to post printed media,so perhaps you could post Mercruiser S.B. 87-14 for me.Every spring a few of my customers get to read it.
And weep.

DHP

 

[Bondo]

Re: Freeze Plugs aren't there to protect from freezing!

Ya know what is really funny. When in school many years ago, some one said I should take typing. I said why, I ain't gonna be a secretary (Circa early 60's).......... guess I should have listened.

Ayuh,........ I remember the Exact Same conversation in the Early 70s........Now I'm stuck typing with 1 finger.....

Don, undoubtedly you are correct, howsomever on two occassions I have been lucky with ford 302's. They popped the "plugs' out instead of breaking the block.

That usually only happens when there's a Light Freeze,... A Coreplug Pops,+ the water Drains.....
In a Hard Freeze,.... The Coreplug Might Pop,.... But nothing Drains,+ the Block is the Next thing to Pop.......

 

[Don S]

Re: Freeze Plugs aren't there to protect from freezing!

DHP,
I added a link to the SB in my original post. On page 2 of the SB, it also shows damage to the impellers from running without water

 

[Don S]

Re: Freeze Plugs aren't there to protect from freezing!

^^^^^^^^^^^^^^^
Bump

Hoping more of the broken block/water in the oil crowd sees this.

 

[DHPMARINE]

Re: Freeze Plugs aren't there to protect from freezing!

Don,Thanks very much for posting that.Seems customers tend to believe it when they see it in print.

DHP

 

[Coors]

Re: Freeze Plugs aren't there to protect from freezing!

Bond-o, I have learned(I elected to take adding machine in school, as it had less keys) that if I let go of the mouse, I have one finger on each hand- two finger typing!

 

[stevieray]

Re: Freeze Plugs aren't there to protect from freezing!

Ayuh,........ I remember the Exact Same conversation in the Early 70s........Now I'm stuck typing with 1 finger.....

Wow, 11000+ posts with one finger - now that's hard work! I became real good at typing one-handed with the onset of on-line dirty movies.

 

[cjames]

Re: Freeze Plugs aren't there to protect from freezing!

I've been lucky enough not to ever have a rawwater cooled block in a boat... I just make sure the coolant is in good shape, and drain the risers and heat exchanger, and forget about it. Whose bright idea was a raw water cooled block anyway?

 

[Scaaty]

Re: Freeze Plugs aren't there to protect from freezing!

I've been lucky enough not to ever have a rawwater cooled block in a boat... I just make sure the coolant is in good shape, and drain the risers and heat exchanger, and forget about it. Whose bright idea was a raw water cooled block anyway?

Kinda off subject, as ANY sand cast motor has core plugs...
see ya in the PCN...do saltwater?...Yeah, your OK..just drain and forget...(Probably read the Manual for stem to stern too, right?..​

 

[MacGyver76]

Re: Freeze Plugs aren't there to protect from freezing!

Thanks Don for the post.. This was interesting reading. I have read alot on this forum and am very impressed with the type of help that is recieved. I will have a question soon and hope will get the great knowlodge of the great members of this board.
I have saved that pdf on my server for later retreaval.

Thanks again and keep up all the great work.

This is my first post