Logo
FULL SITE MENU

Mysterious Milky Oil - Not Risers...

M

mvinesmusic

New member
I have been chasing the cause of water in my oil for a few days. I first narrowed it down to the starboard side of my block. I found this out when I removed both the risers and found water down inside of the starboard manifold, and water vapor throughout the riser. So I thought that the pooled water inside of the manifold had to be from a bad gasket between the manifold and riser. I put on a fresh gasket sealed it up nice and tight, drained the old oil, new filter, and filled with fresh oil. Started up after ran okay for about 2min, then I noticed the same symptoms of bogging down. Shut it off, and checked the oil, and sure enough it showed milky signs.

So after come choice words, I took the riser back off, as well as the manifold, and I believe I see the flow of the troublesome water. I just need to know where you all think it is actually coming from. In the videos below you can see a small hold in cylinder 2 at the top, and it looks like the water is coming through there. Does anyone know what that hole is for, and how/why water is going in it?

Thanks!!

 
There are a few ways to test.

If this is isolated based on your images to one cylinder then as suggested it could be a hole or possibly a bad head gasket on that cylinder.
First I would perform a compression test or leak down test which might reveal a bad head gasket if that is the root cause which would eliminate the need to pressurize the cooling system so you may want to start there

The cooling system is a "closed" system so to speak. Water in, Water out.

If you remove the elbows, Make a block off plate and gasket and mount it to the exhaust manifold surface sealing it completely, both left and right sides. You can then pressure check the system with either Air or Smoke.

Remove the thermostat for this test also to allow the cooling system to be completely open on the engine. Use a new gasket or quality RTV to seal thermostat housing back in place for testing.

Remove the incoming water hose at thermostat housing and make a new hose and adapt/reduce it to a smaller hose to allow some kind of connection to pressurized air or smoke.

If this engine has experience over heating, your issue is common on the V6 engines. Just need to find the root cause.

These are my suggestion.
 
towards the end of the first video, it looks pretty clear that the water is flowing out of the head just behind the valve guide...that suggests the head is cracked and needs to be replaced....

As Kghost suggests, pressure testing the block with show most of the issues
 
Looks like water has been coming in for a while by the amount of corrosion in the ports. Pressure test the engine at best you will need new or reman heads, worst case new engine.

is this a salt water engine ? they tend to rot behind exhaust valves or if over heated can crack there.

Pressure test and get the head off or look with scope camera in cylinders for corrosion. If you have pitting in cylinder walls get a new long block and exhaust
 
I think you posted this same question over at the Hull Truth forum and I responded there; looks like you have a cracked or rotted through cyl head, it can be fixed if the lower end (block & rotating assembly) is still in good shape, but you want to verify that first. That is a pre-vortec 4.3 V6, you can buy remanufactured cyl heads for it for not much money and at the same time I'd replace the cyl head bolts, clean out the bolt holes in the block with a thread chaser, and install the reman cyl heads with a set of Fel Pro marine head and intake gaskets.
I'd consider doing a compression test, however due to the water leak and corrosion on the exhaust valves, the results could be low even if the cyls/pistons/rings are OK. Agree with checking the cyls with an endoscope they make really nice ones not for not that much money. That's a pretty big water leak.
 
kghost said:
There are a few ways to test.

If this is isolated based on your images to one cylinder then as suggested it could be a hole or possibly a bad head gasket on that cylinder.
First I would perform a compression test or leak down test which might reveal a bad head gasket if that is the root cause which would eliminate the need to pressurize the cooling system so you may want to start there

The cooling system is a "closed" system so to speak. Water in, Water out.

If you remove the elbows, Make a block off plate and gasket and mount it to the exhaust manifold surface sealing it completely, both left and right sides. You can then pressure check the system with either Air or Smoke.

Remove the thermostat for this test also to allow the cooling system to be completely open on the engine. Use a new gasket or quality RTV to seal thermostat housing back in place for testing.

Remove the incoming water hose at thermostat housing and make a new hose and adapt/reduce it to a smaller hose to allow some kind of connection to pressurized air or smoke.

If this engine has experience over heating, your issue is common on the V6 engines. Just need to find the root cause.

These are my suggestion.
Click to expand...
A closed cooling system has a heat exchanger and the raw water only serves to keep that cool- it doesn't circulate through the engine.
 
mvinesmusic said:
I have been chasing the cause of water in my oil for a few days. I first narrowed it down to the starboard side of my block. I found this out when I removed both the risers and found water down inside of the starboard manifold, and water vapor throughout the riser. So I thought that the pooled water inside of the manifold had to be from a bad gasket between the manifold and riser. I put on a fresh gasket sealed it up nice and tight, drained the old oil, new filter, and filled with fresh oil. Started up after ran okay for about 2min, then I noticed the same symptoms of bogging down. Shut it off, and checked the oil, and sure enough it showed milky signs.

So after come choice words, I took the riser back off, as well as the manifold, and I believe I see the flow of the troublesome water. I just need to know where you all think it is actually coming from. In the videos below you can see a small hold in cylinder 2 at the top, and it looks like the water is coming through there. Does anyone know what that hole is for, and how/why water is going in it?

Thanks!!

Click to expand...
Where are you located, what is the typical low temperature during Winter and how to you Winterize the boat/engine?

If the temperature drops and the engine isn't drained properly, this is one of the possible results. Another cause is due to a casting that has voids and you would have had a hard time preventing that leak.

My boat was owned by someone who redefined 'overheat' and in the process, an exhaust valve bent. I took the head in and had it checked for leaks through a process called 'Magnaflux'. I would recommend that you do this before anything else- they'll probably media blast it and if no leaks are found, it will need to be repainted, but if it turns out to be OK, that's not the worst thing. I'm not optimistic about it being free of cracks, though.
 
jimn said:
A closed cooling system has a heat exchanger and the raw water only serves to keep that cool- it doesn't circulate through the engine.
Click to expand...
Sorry, I didn't see who I was replying to and I missed the end of the time for editing or deleting but I can't agree with calling it a closed system.
 
Back
Top