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Re: Freeze Plugs

To: Paul Hunt <>
Subject: Re: Freeze Plugs
From: Charles & Peggy Robinson <>
Date: Fri, 15 Oct 2004 15:06:04 -0500

     I had a small block chevy V8 that froze up the one time in my life 
that the temp went below 0 deg F in El Paso, TX.  I had loaned the car 
to a relative, he was supposed to put antifreeze in it. Anyhoo, it 
popped out a couple of "freeze" plugs AND cracked the block between the 
two holes.

   Paul, the term I learned was "Welch" plugs, named after the guy who 
came up with the concave plugs that are expanded by peening and that 
we're discussing here.  There are other types, as I'm sure you know. 
Some plugs cover holes left by the molds and for mold material removal, 
others cover holes put there for internal machining access, such as the 
holes for machining the cam bores on some blocks.



Paul Hunt wrote:
> Unless your coolant is very low all of them are below the level of the
> coolant, which is why they weep when they start corroding through or there
> is a bad edge seal, but I'm not saying they would pop in a freeze.  They are
> not machining access holes either, just a side-effect of the casting process
> as you say, which is why they are known as 'core plugs' in my experience,
> the 'core' being the inner part of the casting mould.
> ----- Original Message -----
> From: <>
> To: <mgs@Autox.Team.Net>
> Sent: Thursday, October 14, 2004 5:08 PM
> Subject: Freeze Plugs
>>First, they really aren't "freeze" plugs, since they wouldn't pop if the
>>coolant froze; they're too high up in the block. They're machining plugs
> and an artifact of the way the engine is cast.

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