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Freeze plugs

N

NewEngland

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"I just started my Ford 302 me

"I just started my Ford 302 mercruiser for the first time this season. It started fine and ran good but then began pouring water out of the mainfold, it is raw water cooled.The manifold has round plug type fitings.One of these plugs was blown out and the water went right through into the bilge.Are these freeze plugs or somthing like that to prevent the block from craking if it freezes, and is it possible to replace them without installing a new manifold?"
 
"They're actually casting

"They're actually casting plugs, used to remove the sand when the parts are made. They happen to work as freeze plugs but it's best if they never pop out. This indicates that the winterization process wasn't done properly."
 
"JB Weld wouldn't allow th

"JB Weld wouldn't allow them to pop out if it freezes, would it? They are pressed in, the surfaces need to be clean and no adhesive should be used.

If one or more popped out, I would recommend making sure nothing bloke as a result of freezing, like the motor and exhaust manifolds (internal cracks)."
 
How would I know if somthing i

How would I know if somthing internal was cracked?The motor ran good when it was started.What can I replace the "casting plugs"with?
 
"The plugs are NOT designed to

"The plugs are NOT designed to "pop out". They're merely there to allow the sand to come out doing casting (as stated above).

you need to detemine WHY the plug popped out. If it's cracked inside as I suspect, running the motor could hydro a cylinder!

Jeff"
 
"It could hydro a cylinder or,

"It could hydro a cylinder or, like the 351 I had to ask why it had problems due to the fact that the customer didn't bother to tell me that it had overheated and frozen- just that he thought it needed a tune-up, the cylinder wall cracked and was catching the piston skirt and causing it to knock badly."
 
"The plug was reinstalled and

"The plug was reinstalled and the engine started up and has run good for the most part.However you say that it could be a craked cylinder.The temp is good and the oil is new and looks good,There is no water in the oil.Whatelse would I look for to determine the extent of the damage.The engine was winterized with the "pink stuff"at the end of the season,It was pump through the engine and flowed through the exhaust ports on the leg.Could it be that the only damage was the plug coming out?"
 
"It could be the only damage,

"It could be the only damage, but it could show up later, too. If the pink RV stuff was run through, it may not have been enough. I don't use less than 5 gallons when I winterize and I check what's in the block when I'm done."
 
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