4.3 omc water in oil

[crazylegs68]

I have a 1988 4.3 omc that got water in the oil last year I am going to try to resolve it this year I have the engine out and oil pan off inside the engine looks good I am going to replace the rod and main bearings and the engine should be fine but I have to find the cause of the leak before proceeding. I have read on here about the exhaust manifolds leaking or the shutter valve going bad if that is the case how does that get water in the oil?
I can rig up a tester for the exhaust manifold and pressure test it how is the shutter valve supposed to work?

also what other issues might cause this that are common? like what I should look at first and what I better look at before I put the engine back.
thank you for any and all help.
Ben

 

[crazylegs68]

Re: 4.3 omc water in oil

I forgot to put this in the posting.
I am new to this forum and I have searched on here (excellent site by the way very informative thank you for that)for the answers, however I have not found exactly what I am looking for.

 

[crazylegs68]

Re: 4.3 omc water in oil

Ok I just pressure tested the coolant system and hear a leak at the #6 cylinder which is where most of the discoloration (ie rust) is at, I noticed when I removed the motor that the right exhaust manifold had water in it right inside the lip in the exhaust port. That is why I had the questions about the exhuast manifold leaking. I am still not convinced it is the head or the intake yet because I had the two intake manifold bolts out at the back right water port to remove the shifter bracket so that may have let the intake seal loosen enough to leak so I am now going to start removing it and see where that leads me.

any other ideas?

 

[bruceb58]

Re: 4.3 omc water in oil

If you pressurised the coolant system and detected a leak like you describe, it won't be the exhaust manifold because there are no water passages between the block and the exhaust manifold.

 

[Dakota47]

Re: 4.3 omc water in oil

cracked block.

 

[crazylegs68]

Re: 4.3 omc water in oil

more to the story,
I pulled the intake and head, I cannot find any fault with either one of the gaskets, but all three cylinders on that bank are affected the center one the least. cyl. 2 and 6 look about the same both with discoloration in them and rust on the head itself inside. I also noticed rust in the valleys inside the intake only on the right bank (same side as the cylinder problem). if it is a cracked block how likely is it to only affect two of the cylinders and especially not next to each other? what about the intake rusting through is that likely or anyone ever heard of this? the reason I am asking I wouldn't think the water would travel back into the intake from the cylinder.
thanks
Ben

I will try to get pics posted.

 

[crazylegs68]

Re: 4.3 omc water in oil

ok I don't know how to add pictures can someone help me.
thanks

 

[Deanrw3]

Re: 4.3 omc water in oil

1. Make an account at photobucket.com
2. Upload your pic there
3. Copy the link that photob gives you for posting in forums
4. Hit the little button that says "insert link" (world with a chain, Above) on the forum page
5. Click post


gL


Dean

 

[crazylegs68]

Re: 4.3 omc water in oil

http://s288.photobucket.com/albums/ll178/crazylegs1968/?action=view&current=IMG_0819.jpg
http://s288.photobucket.com/albums/ll178/crazylegs1968/?action=view&current=IMG_0820.jpg
http://s288.photobucket.com/albums/ll178/crazylegs1968/?action=view&current=IMG_0818.jpg
http://s288.photobucket.com/albums/ll178/crazylegs1968/?action=view&current=IMG_0821.jpg
http://s288.photobucket.com/albums/ll178/crazylegs1968/?action=view&current=IMG_0822.jpg
http://s288.photobucket.com/albums/ll178/crazylegs1968/?action=view&current=IMG_0823.jpg

I hope this works
I did a thourough inspection of everything and I found a spot under the head gasket coming from a water port that is a light trail of rust like maybe the gasket failed that is the last three pictures what do you guys think. could this allow all three cylinders and the intake to be affected or is it just wishful thinking?
thanks
Ben

 

[jerryjerry05]

Re: 4.3 omc water in oil

If only one side is affected. Then it is probably the exhaust manifold.Then it depends on which type you have.Post a pic of the manifold.Jerry

 

[crazylegs68]

Re: 4.3 omc water in oil

http://s288.photobucket.com/albums/ll178/crazylegs1968/?action=view&current=IMG_0824.jpg

here is a picture of the manifold the insides of it look good from what I can see and that is not much I don't have a way to pressure test it right now.
I think I am going to buy a new head gasket and intake manifold gasket, put it on a pressure test it and see if there are any leaks if there is then I am just out the gaskets if not then I will move on and consider that the problem.
any suggestions on that? Or other ideas I am open to any and all.

 

[bruceb58]

Re: 4.3 omc water in oil

If only one side is affected. Then it is probably the exhaust manifold.Then it depends on which type you have.Post a pic of the manifold.Jerry

He did do a pressure test and heard a leak near cylinder #6. If the manifold is leaking, that would be an additional problem to what he has.

 

[crazylegs68]

Re: 4.3 omc water in oil

went and bought the cheapest gaskets I could find at advanced auto and they turned out to be felpro, any way I installed temporary the head and manifold torqued it all down plugged everything back up and pressurized the coolant system and as of 20 minutes ago it is holding 20 psi so I do believe that was the problem. it did leak down just barely but I sprayed the hoses with soapy water and found a very small leak and I am sure that is where it is coming from.
the only thing I can think of for all three cylinders being affected, is because when the engine was shut down all the coolant above that level would run down into the cylinder until it is full and then run to the other ones and into the open valves. just a thought because that was/is confusing me.
any input?
thanks
Ben