Freze Plug

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fastmopar

fastmopar06
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WELL..... My 72 has been out in the driveway for a couple of single digit temperature days. I moved it into the Garage this last weekend then went out to clean up the driveway. A freeze plug was sitting there. The engine had H2O, no antifreeze in it. Had not progressed to the antifreeze level yet.

Anyway, since the freeze plug popped am I looking at cracked block?

I figure I'm going to have to pull the engine/trans anyway to fix the leak in the trans, so....

Just wanted some oppinions....

Thanks,

fastmopar
 
Maybe, maybe not. check it over real good and look for obvious signs.
 
Inboard/outboard guys go through it all the time.
Take heater hose,below the thermostat, make a connect to the end for air hose and gauge; Put 10 lbs or air to it. Listen for air; carb, exhaust, oil filler.
They usually crack in the valley.
 
I'm still tryin to figure out why no anti freeze? That was kinda dumb.
 
oh this happens to me when it gets below 10 degrees outside, my freezeplug starts to leak, now in this weather it doesn't do it at all. that is alot though to pop out
 
Hopefully the plug did it's job and the block wasn't cracked. Remember, antifreeze is a coolant as well as a antifreeze. All street cars should have antifreeze in the system. Hopefully no harm was done.
 
Well, he does live in Nevada. Maybe freezing is unusual there. But the plug wasn't really doing its job when it popped out. That's a misconception. It's job is to plug the core hole left in the block during the casting process & keep the coolant in the water jacket, not to pop out when things freeze. That's just a side effect.
 
'64 Cuda said:
Well, he does live in Nevada, but the plug wasn't really doing its job. It's job is to plug the core hole left in the block in the casting process & keep the coolant in the water jacket, not to pop out when things freeze. That's just a side effect.
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I can't help but disagree. The core plugs are there to plug the holes from the block casting process but they are also called frost plugs that will pop out when water freezes and expands in the coolant passages. From Wikipedia:


Freeze plug

A true freeze plug is an expansion plug located in the side of an engine block that is supposed to protect the block against freeze damage. Water expands when it turns to ice, and if the coolant does not have enough antifreeze protection it can freeze and crack the engine block. The freeze plugs (there are usually several) are supposed to pop out under such conditions to relieve the pressure on the block.

There is also an explanation of a "core plug" which is one and the same.
 
Want me to search for more info somewhere else? I was just trying to prove my point. Live in a warm climate? Use water in your cooling system. I will use antifreeze/coolant to keep it from freezing and to help it cool better in warm weather. Antifreeze also has anti-corrosive chemicals, anti rust, and water pump lube. And yes the core plugs also are frost plugs to help prevent block breakage when water freezes. They aren't a cure all though. I rest my case.
 
toolmanmike said:
yes the core plugs also are frost plugs to help prevent block breakage when water freezes.
Click to expand...

Sorry Mike, you lose this one. In a previous life I sold auto parts, and a friend of mine and I junked out no less than 5 Mopars in about the same amount of years that we got cheap -- because they froze and broke.

MANY MANY old school mechanics --before the www-- told me exactly the same thing. --- "Freeze plugs" are "an old wives tale." The term PROBABLY got started BECAUSE they actually do pop out, but there are there for ONE THING ONLY, and that is the cores for casting the block.

They are absolutely positvely NOT there to protect the block, they do NOT protect the block and certainly should not be relied upon for such


PROOF?: You will NEVER FIND in ANY shop manual, mechanics manual, manual manual, or any other kind of reliable, recognised text or schoolbook printed anywhere that "freeze plugs" protect an engine.
 
Well ,this is never ending discussion, just a matter of opinion. I never said that the plugs were designed just for freeze protection. They are designed for core sand removal but are also called freeze plugs or frost plugs and can and will pop out of the block to help prevent block cracking. Blocks can still crack when frozen but may be saved because the plugs pop out creating room for the freezing water when it expands. My original post said "hopefully the plug did it's job and the block wasn't cracked". Where in that sentence did I say that frost/freeze plugs are not core plugs. I'm done here!

http://www.yourautonetwork.com/freeze_plug.html
http://www.econofix.com/frezplug.html
http://www.imperialinc.com/grp293.shtml
http://wiki.answers.com/Q/What_is_a_frost_plug
http://autorepair.about.com/cs/generalinfo/l/bldef_233.htm
 
I gotta agree with 67... They are sand core plugs and just happen to pop out when the block get's under pressure during a freeze. If you think otherwise, ask yourself how the heads crack on the exh flange side when they freeze but the core plugs in the heads don't pop out...
To the OP... I'd be very careful looking the block over when it comes out, and if possible, let it thaw, then use a radiator pressure testor to pump up the cooling system to 15psi or more. If the pressure drops and you cant see a leak like a hose lose or something, there's a very, very good chance the block has a crack. I have seena valley crack, but most of the time the valley cracks and main cracks are not from freezing but from use. The sides of the block crack from freezing, and the heads along the bottom edges near the head bolt flanges. Least that's my experience.
Also, if you run water and the car is sitting for more than a week in climates that have ever experienced a cold snap... Drain the block. It's as simple as removing the screw in drains in the sides of the block and replacing with radiator petcocks.
 
Keep this in mind. A lot of people believe the plugs pop out because frozen coolant/water pushes them out. That ain't how it happens. The frozen coolant/water distorts the block enough that the plugs come out all on their own. Think about that.
 
Kernel Sanders said:
Doesnt antifreeze also contain a rust inhibitor?
Click to expand...
Almost all of them do.

Kernel Sanders said:
I also though that antifreeze also transfers heat better than str8 water too.
Click to expand...
Anti-freeze not only lowers the freezing point of the water it's mixed into, but it also raises the boiling point.

To the OP, check very carefully around the hole that the freeze plug popped out of. If there's a crack in the block, it will most likely be in that area. You'd do well to pop the heads off and make sure there are no cracks in there. I'm hoping this is not a 340 with W2 heads or something like that. If it were I'd be kicking myself vigorously for not putting anti-freeze in it.
 
Guys! Jeeze.... Just wanted a little feed back onwhether the block might have cracked.

Didn't want to start WWIII.

I didn't have antifreeze in it because I was not sure I wasn't going th have to pull the Engine/Trans again.

And yes, no matter what the "real" function of a FREEZE plug is, it popped out from the water in the bolck freezing. I'll let you know what I find when I pull the engine/trans back out.

The engine is a 60 over 318 with 360 heads and edelbrock intake.
 
Antifreeze lowers the freezing point,raises the boiling point and reduces the calories per gallon that the mix absorbs per degree of temperature change. However the higher boiling point more than makes up for the difference. If corrosion were not an issue ( yes antifreeze has inhibitors and pump lubricants as well) and the temp would not go above boiling ( at system pressure) straight water will carry more heat. Since corrosion IS a factor and freezing IS a factor I would not recommend ever leaving a cooling system with just water.
The core plugs, if they do pop out when a block freezes, usually do so because of distortion of the openings.
 
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