4.3 that I was not winterized

[Gerhard Peters]

I bought a boat, knowing that the engine was not winterized. It is the 4.3 Chevrolet V6. I have swapped and rebuilt a few of these engines, so I'm very familiar with them. While the engine was still in, I had it running with water connected. I noticed that the freeze plugs popped, and both the manifolds had cracks. So I pulled the engine out. I saw that it did not have that little plate on the block with the serial number I'm used to. I found a different little plate attached to the engine. I'm attaching a picture of the plate because I'm wondering what it represents.
I figured that the engine had to be replaced at one point. The boat is a 2004 Hurricane.

I pulled it and have the engine apart now, and it is virtually new. It still has the cross-hatching from the cylinder honing, so it is not even fully broken in yet. The bottom end looks brand new.
I can't find any cracks anywhere so it seems that the freeze plug prevented it from cracking the block. The last 4.3 I took apart about 5 years ago had a large crack in the water jackets between cylinder bores.

Is it possible that I could have hairline cracks that are not visible to the eye? How could I test for potential cracks that I would not be able to see

Here is the image of the plate on the engine. The number is 140198

 

[Scott06]

Pressure test the cooling system. Normally a 4.3 will crack in lifter valley just below the heads

tag probably means it is a rebuild.

if you need a 4.3 ( block verified cracked) just figure out your block casting number and get a $400 from a wrecking yard.

 

[crazy charlie]

I bought a boat, knowing that the engine was not winterized. It is the 4.3 Chevrolet V6. I The boat is a 2004 Hurricane.


Is it possible that I could have hairline cracks that are not visible to the eye? How could I test for potential cracks that I would not be able to see

Here is the image of the plate on the engine. The number is 140198
View attachment 405381

I had my heads magnafluxed years ago and discovered cracks that were not visible to the naked eye around the valves. Pretty sure thats what it was called. Looked like a big magnet was attached to the heads and metal filings were spread out on the suspect areas and VOILA the cracks were then visible in the filings.I would assume you can do that to your suspect area.Charlie

 

[Scott Danforth]

core plugs are there to get the core sand out of the block. no such thing as a freeze plug. No GM block survives a freezing. only some ford blocks do.

pressure test the cooling water jacket to 15psi, if it holds, its good.

however since you pulled it apart already, that means you need to put it back together first with new gaskets

 

[alldodge]

Will agree no GM block will survive freezing, that is if block was full of water when it happened. If the block was half full it will because it happened to my 454

Was draining everything when I got distracted and forgot to drain one side of the block. Spring came and found water and 2 core plugs out. Reinstalled plugs and boat ran several years after until I sold it without issue

 

[Gerhard Peters]

core plugs are there to get the core sand out of the block. no such thing as a freeze plug. No GM block survives a freezing. only some ford blocks do.

pressure test the cooling water jacket to 15psi, if it holds, its good.

however since you pulled it apart already, that means you need to put it back together first with new gaskets

I know. Everyone calls them freeze plugs, and like @alldodge I have seen engines where the "freeze plugs" kept the block from cracking. They poped, and the block was fine

 

[Gerhard Peters]

This is what I will do
Buy a cheap set of head and intake gaskets
Put the heads and intake back on
Create a block of plates for the water pump
Create a plate for the thermostat hole so that I can hookup air

Crossing my fingers.

 

[Bondo]

I know. Everyone calls them freeze plugs, and like @alldodge I have seen engines where the "freeze plugs" kept the block from cracking. They poped, and the block was fine

Ayuh,...... That can only happen when there is a light freeze, the core plugs pop, 'n the block self-drains, before a winter long deep hard freeze occurs,.....

 

[Gerhard Peters]

Ayuh,...... That can only happen when there is a light freeze, the core plugs pop, 'n the block self-drains, before a winter long deep hard freeze occurs,.....

That makes sense. I have seen it a few times in my lifetime working with engines.

 

[Gerhard Peters]

Put the heads and intake back on with new gaskets and created block off plates. Pressurized to 15 psi. No leaks holds steady pressure. I got lucky.

Also checked the pistons and they are .40 over so it is a rebuilt engine.