OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

[mept]

This is the situation... My boat is an 88 fourwinns I have owned for 17 yrs, last year I discovered a manifold crack and had it welded, I believe it was JB welded but I don't know anything about welding. I had winterized the boat the same as previous yrs so I don't know why it happened, also the freeze plug popped too on the same side. Following the weld fix, I started the boat, the weld appeared to be fine, but additional leak was occurring directly below at what seems to be the head gasket.
Q1: If no internal damage of the exhaust manifold exists, would the engine operate without risk of water entering the cylinders? (at least from this specific spot)
Q2: If a gasket leak exists, is it possible that water would escape outward without entering internals?
Q4: What would be the obvious signs of head or block damage?
Q5: When I drain the oil tomorrow, it should be clear whether water entered the engine correct? (no foamy white conditon is observed, but boat was last run over 1 year ago)
Q6: What if I had never heard of this web site and the knowledgable people here until after I tore my engine half way down (heads and manifolds off and accessory items in the way) Where should I proceed to prevent only temporarily having to return to fix a bigger problem then I might already be facing?

Thanks for all your knowledgable support to boaters, and novice mechanics like myself.

 

[bruceb58]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

You should buy new manifolds. You are risking an expensive engine on a manifold that could easily be cracked internally.

On second thought, your expensive engine may already be toast. You need to pressurize the cooling system to see if its cracked internally/externally as well.

 

[Bondo]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

You should buy new manifolds. You are risking an expensive engine on a manifold that could easily be cracked internally.

On second thought, your expensive engine may already be toast. You need to pressurize the colling system to see if its carcked internally/externally as well.

Ayuh,.... It shoulda been pressure tested when the manifolds were welded....
Testing saves Good money you could be spending on a Complete replacement....

 

[mept]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

If the block is cracked, is their a typical area which the damage occurs? Is it something you can visually inspect and see?

 

[Bondo]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

If the block is cracked, is their a typical area which the damage occurs? Is it something you can visually inspect and see?

Ayuh,... Many times in the lifter valley, or along side the lower block, Inside, behind the drain plugs...
Ya usually don't See 'em til the motor is Out, 'n on a stand...

 

[mept]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

So what are the chances of having a non-visible block or head crack at the mating surface where a leak was visible when running? Can a crack not along the exterior surface have enough water pressure to force a leak between the two appearing like a gasket leak?

 

[xdgt03]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

A freeze plug popping is a concern but it did what it is designed to do, hence the name. If it is leaking at what seems to be where the head and the block meet then it can easily be the head gasket. Some water jackets run near the edge there. I would check my oil to see if it looks like chocolate milk. That would indicate that water is leaking into the oil. That does not rule out a cracked block but either way you are looking at removing the head.

 

[bruceb58]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

A freeze plug popping is a concern but it did what it is designed to do, hence the name.

Too bad they aren't called freeze plugs and tey do little to prevent a block from cracking.

 

[gbeltran]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

A freeze plug popping is a concern but it did what it is designed to do, hence the name.

They are actually core plugs, used to plug the holes from the mold in the casting process. If they were actually "freeze" plugs, you wouldn't have people posting about cracked blocks, and they wouldn't have such a lip holding them in, if you have ever changed one you know what it takes to pop them out.

 

[ENSIGN]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

I'm glad you didnt winterize mine save up and buy a engine and manifolds

 

[sea wolf]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

I'm glad you didnt winterize mine save up and buy a engine and manifolds

Never made a mistake workin' on your boat? Give the guy a break, nobody's perfect.

 

[mept]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

ensign, Yes I did the exact same process for winterizing my boat for over a decade with absolutely no problems. 17 years of boat ownership, but clearly having any kind of problem does not make me some "expert" so you need to find the time to be an ***. Your not funny and your not helpful, feel free to post elsewhere, otherwise please just **** off.

 

[xdgt03]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

They are actually core plugs, used to plug the holes from the mold in the casting process. If they were actually "freeze" plugs, you wouldn't have people posting about cracked blocks, and they wouldn't have such a lip holding them in, if you have ever changed one you know what it takes to pop them out.

Yes Yes. They are core plugs for the casting process, but have routinely for a hundred years been called freeze plugs too. And they do "pop" if water freezes in the block without blocks cracking. Hence the name freeze plug. And you can buy replacement "freeze plugs" from every auto parts store including Summit Racing which calls them by all things, "freeze plugs". If you have worked on motors you would know this. Thanks for your technical correction tho.

They fail mostly from corrosion. Water freezing in the block can also cause the block to crack but it is not a certainty.

It may in fact be a cracked block but there are lots of other things that it could be including the blown head gasket. Everyone jumped to the cracked block without giving many other possibilities. You could cause him to spend a lot of time and money looking for a new motor, or junking a boat, when it could be a rather easy and comparatively inexpensive fix.

 

[mept]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

Update to initial post...
Drained the oil this weekend, and the oil had no water, or change in color/consistancy other then looking like typical dirty oil. Total volume removed was close to capacity but I used an electric pump to remove the oil so it might be just what it would let me pump out.

So if the block or head was cracked, would water be almost certain to be in the pan? (the engine was run on muffs when checking the initial manifold repair)

My next plan is to reassemble with new gaskets and perform a compression test. Any further thoughts on what the main problem could be or any further tests I should perform would be greatly appreciated.

 

[mept]

4.3L possible head gasket leak or something worse???

4.3L possible head gasket leak or something worse???

This is an updated repost regarding my problem with my 4.3L OMC engine.
The boat is an 88 which I have owned for about 17 yrs.
The freeze/core plug popped starboard side, about 3yrs ago and was put back in. I had no further problems that year.
The following winter the plug again popped out and also the manifold on the same side had cracked.
Manifold was repaired and plug put back in, upon testing their seemed to be a gasket leak between head and block adjacent to where manifold damage occurred.
I tore engine down to replace gaskets (but found I should have done a compression test first)
I have removed the oil and found it to be dirty from the last seasons use, but of normal oil consistency. I don't think any water had entered the oil pan based upon this.

So where do I go from here? What do the experts here think happened?
I am hoping I will find that I did only suffer a gasket failure.
I think I should also replace the freeze plug, but not sure how to get it back out now.
I was also planning on a compression test once reassembled.
Any thoughts would be greatly appreciated.

 

[Bondo]

Re: 4.3L possible head gasket leak or something worse???

Re: 4.3L possible head gasket leak or something worse???

Ayuh,... Put it together, 'n Try it....

Also,... Learn how to properly Winterize it, ya goofed it up twice, 2 years runnin'....
Learn how to DRAIN it...
Air Don't Freeze...

 

[mept]

Re: 4.3L possible head gasket leak or something worse???

Re: 4.3L possible head gasket leak or something worse???

Besides draining the 2 petcocks on each side of the engine, and removing the hoses to drain as well, I am not sure how I could drain the boat further. Now if their is any other way to ensure the boat is properly drained I am all ears. I did manage to do it for 15 years without problems, but I am open to any suggestions. My post however had to do with something else entirely.

 

[Bondo]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

but additional leak was occurring directly below at what seems to be the head gasket.
Q1: If no internal damage of the exhaust manifold exists, would the engine operate without risk of water entering the cylinders? (at least from this specific spot)
Q2: If a gasket leak exists, is it possible that water would escape outward without entering internals?
Q4: What would be the obvious signs of head or block damage?
Q5: When I drain the oil tomorrow, it should be clear whether water entered the engine correct? (no foamy white conditon is observed, but boat was last run over 1 year ago)
Q6: What if I had never heard of this web site and the knowledgable people here until after I tore my engine half way down (heads and manifolds off and accessory items in the way) Where should I proceed to prevent only temporarily having to return to fix a bigger problem then I might already be facing?

Ok,... So yer chasin' a visible water leak at the head, at the gasket line, or very close,..??

Have you sent the heads to a machine shop for a cleanin', tweetin', 'n ispection,..??
I would...

If the heads check out, throw it together, 'n Try it....

Q1 is a Roll of the Dice,... Yer roll, not mine...
Q2 is a Yes, as I've just gone through it on vortec heads,...
The heads were also cracked, 'n replaced...
No Q3,..??
Q4, Cracks,... Look really, Really closely on it's side, along the top of the block, just below the deck...
Q5, ya drained it, 'n it's fine...
Q6, see my answer above,..

I had winterized the boat the same as previous yrs so I don't know why it happened, also the freeze plug popped too on the same side. Following the weld fix,

Ayuh,... Learn how to DRAIN it, 'n this stuff don't happen,...
Air just Don't Freeze....

 

[Lou C]

Re: OMC 4.3L Ex. Manifold repaired, possible gasket, cyl. head, block damage???

When you drained, did you rod out the drain hole, rust can clog the hole and not let all the water drdrain. Also you have to pull off the bottom end of the big hose that goes from the thermo housing to the circulating pump on the front of the engine, that area holds a lot of water. You also have to rrod out the ones in the manifolds too.