Head Gasket / Milky Oil

[TyeeMan]

Three years ago on a different boat I had exhaust manifold/riser fail which lead to water in the oil. I changed the oil twice and it still took about 3 hours of in-lake running to finally get to a point where there was no moisture on the oil fill cap.

 

[nola mike]

If you're reintroducing water to the pan, your oil level in the dipstick should rise

 

[Jon1229]

20 min at idle will not "cut" it. You must run it for at least long enough to get the oil up to full operating temp. That usually means 30 min or more at normal cruising speed. (and that's every time between oil changes)

Also, draining the oil the "regular" way, I.E. sucking it out of the dipstick tube, doesn't usually get the last little bit out of the bottom of the pan where you might have a "Water-line""

If a couple of changes do not reduce the water, you should pressure check the cooling system to rule out block/head cracks and/or gasket leaks.

The block should hold 15-20 PSI for at least an hour or 2

Close off all openings using any plumbing fittings/hoses etc you can find, connect a valve and a gage (between the valve and the block) , pump it up, close the valve and turn the compressor OFF and listen. If it's leaking, you'll hear it.

Thanks I plan on doing the pressure test tomorrow. Maybe wishful thinking but I wouldn’t think the block would be cracked because it wasn’t milky all year and now it’s milky after doing the gaskets. I’m took it out last night and the oil got milky and the level also went down not up. There is also milky oil water in the bilge so it’s clearly escaping somewhere. What I noticed last night was that there are some rust stains around the exhaust elbow gasket that definitely weren’t there before, and the head bolts had little pools of water around them.

 

[wahlejim]

It sounds like you have more than one issue right now, those being:
1) Milky Oil
2)Exhaust gasket failure
3) Oil Leak

Milky oil and Exhaust Gasket go together. That system has to be air tight or water can leak back into your engine, causing milky oil. With the amount of times you have been in there with the head gasket, something probably got knocked loose. Drain your exhaust manifolds, change out gaskets, put back together. Double check your hose clamps on your y-pipe to make sure those haven't jarred loose as well. Does your engine struggle to turn over?

Oil leak, just have to track it down. I would start with your head gasket and go from there. I had a similar situation 2 years ago, both with the exhaust system leak and oil leak. Mine ended up being my oil pressure sender. Thread split and leaked oil. A lot of times its the simple things right around where you are working. For me, I concluded that I hit the oil pressure sender when I had the valve cover off replacing a rocker that broke on me. It is easy to get frustrated at these things and force things where they shouldnt go

 

[HT32BSX115]

Milky oil and Exhaust Gasket go together

Actually they don't.
By "Exhaust Gasket" I assume you mean Exhaust riser gasket.

When the engine is running, water due to an exhaust riser leak doesn't get back into the engine because the water gets "pushed" out with the exhaust.

Once the engine is shut down, water that comes back into the engine from a leaking riser gasket can only be up to that amount that is above the riser gasket immediately after the engine shuts down and on one side, it's somewhere around 1/2-1 cup.

But since riser gasket leaks are not "floods" the actual amount of water that can leak back before the riser water level drops below the gasket, is small. (not usually enough to cause "milky" oil)

Once the engine stops turning, the water level in the riser begins to drop immediately..... so not all the water can leak into the exhaust and that water that does end up running into the 1 or 2 exhaust valves that happen to be open tends to be a very small amount.

If you try to start the engine immediately after shutdown, that little bit of water (usually on the order of tablespoons) can cause a brief hydrolock on initial cranking but many times it briefly slows cranking and makes it seem like the battery is low or the starter is "dragging".


if you leave the engine off for longer more than 30 min or so, that little bit of water will leak right past the rings into the crankcase.

If you later start the engine and run it normally, the water will evaporate quickly and there won't be any visible emulsion.

My previously installed OMG 460 King Kobra had leaking riser gaskets on both sides and I ran it for a whole summer before I removed the risers to replace them.

I found that it would "hydrolock" every time if I tried to start it right away after shutdown, like after picking up a skier..... It always seemed like the starter was weak because it would crank and after start after a few tries.......If I waited for 30 min or more (or overnight) it would start right up and run normally. I checked the oil everyday. No milk.

I NEVER had visible water in the oil. I.E. the oil always looked "normal"

Once I got the heads off the engine, it was pretty clear that there had been water in a couple of cylinders for a LONG time.

Visible water in the oil is almost always due to a much more severe leak into the crankcase........and it's usually due to either a cracked block or less likely a cracked head and even less likely a rotted out intake manifold. (but all those conditions are possible) head gasket leaks do not usually cause water in the oil and compression checks don't tell you anything (about cooling system leaks)

The best way to rule out a cracked block or head, or other leak in the cooling system is to pressure check it using compressed air.

This should be the first thing you do with visible water in the oil.

Cheers,

Rick

 

[Jon1229]

Actually they don't.
By "Exhaust Gasket" I assume you mean Exhaust riser gasket.

When the engine is running, water due to an exhaust riser leak doesn't get back into the engine because the water gets "pushed" out with the exhaust.

Once the engine is shut down, water that comes back into the engine from a leaking riser gasket can only be up to that amount that is above the riser gasket immediately after the engine shuts down and on one side, it's somewhere around 1/2-1 cup.

But since riser gasket leaks are not "floods" the actual amount of water that can leak back before the riser water level drops below the gasket, is small. (not usually enough to cause "milky" oil)

Once the engine stops turning, the water level in the riser begins to drop immediately..... so not all the water can leak into the exhaust and that water that does end up running into the 1 or 2 exhaust valves that happen to be open tends to be a very small amount.

If you try to start the engine immediately after shutdown, that little bit of water (usually on the order of tablespoons) can cause a brief hydrolock on initial cranking but many times it briefly slows cranking and makes it seem like the battery is low or the starter is "dragging".


if you leave the engine off for longer more than 30 min or so, that little bit of water will leak right past the rings into the crankcase.

If you later start the engine and run it normally, the water will evaporate quickly and there won't be any visible emulsion.

My previously installed OMG 460 King Kobra had leaking riser gaskets on both sides and I ran it for a whole summer before I removed the risers to replace them.

I found that it would "hydrolock" every time if I tried to start it right away after shutdown, like after picking up a skier..... It always seemed like the starter was weak because it would crank and after start after a few tries.......If I waited for 30 min or more (or overnight) it would start right up and run normally. I checked the oil everyday. No milk.

I NEVER had visible water in the oil. I.E. the oil always looked "normal"

Once I got the heads off the engine, it was pretty clear that there had been water in a couple of cylinders for a LONG time.

Visible water in the oil is almost always due to a much more severe leak into the crankcase........and it's usually due to either a cracked block or less likely a cracked head and even less likely a rotted out intake manifold. (but all those conditions are possible) head gasket leaks do not usually cause water in the oil and compression checks don't tell you anything (about cooling system leaks)

The best way to rule out a cracked block or head, or other leak in the cooling system is to pressure check it using compressed air.

This should be the first thing you do with visible water in the oil.

Cheers,

Rick

I will be doing the pressure test in the morning, but looking at the engine I’m confused which hoses to clamp and which not to. Any instruction is appreciated!

 

[Jon1229]

It sounds like you have more than one issue right now, those being:
1) Milky Oil
2)Exhaust gasket failure
3) Oil Leak

Milky oil and Exhaust Gasket go together. That system has to be air tight or water can leak back into your engine, causing milky oil. With the amount of times you have been in there with the head gasket, something probably got knocked loose. Drain your exhaust manifolds, change out gaskets, put back together. Double check your hose clamps on your y-pipe to make sure those haven't jarred loose as well. Does your engine struggle to turn over?

Oil leak, just have to track it down. I would start with your head gasket and go from there. I had a similar situation 2 years ago, both with the exhaust system leak and oil leak. Mine ended up being my oil pressure sender. Thread split and leaked oil. A lot of times its the simple things right around where you are working. For me, I concluded that I hit the oil pressure sender when I had the valve cover off replacing a rocker that broke on me. It is easy to get frustrated at these things and force things where they shouldnt go

Thanks i appreciate the help. And no the engine doesn’t have trouble turning over it usually fires right up. Only time it takes a minute is immediately after trailering rather than leaving it in the slip.

 

[Jon1229]

My problem is that I can only find three hoses to clamp not 4. I have a 2001 mercruiser 3.0

 

[Scott Danforth]

disconnect the line from the drive that supplies water and plug it with a gauge and air source
disconnect the two lines to the manifold/elbow and plug
pressure test to 15 psi
turn off air source (closing system)
if pressure drops, you have a crack/leak somewhere

 

[Jon1229]

disconnect the line from the drive that supplies water and plug it with a gauge and air source
disconnect the two lines to the manifold/elbow and plug
pressure test to 15 psi
turn off air source (closing system)
if pressure drops, you have a crack/leak somewhere

Do I need to remove the elbow and cover it so that no air can leave that way? Thank you so much for the response I’m struggling

 

[HT32BSX115]

Do I need to remove the elbow and cover it so that no air can leave that way? Thank you so much for the response I’m struggling

Couple of ways you can do it.

One way is to make up a metal plate (with a homemade gasket)....... remove the elbow and seal the exhaust manifold using the gasket and plate, then you can pressure check the manifold along with the block and head.

But, normally, you want to isolate the manifold and riser from the engine block/head(s). Since manifold leaks don't really result in a LOT of water in the oil, you only want to pressurize the head and block.

The manifold is usually only connected to cooling water via a 5/8" or 3/4" hose etc anyway, so it's much easier to just disconnect the manifold water supply altogether from the cooling system and plug the hose with a suitable plug.

You can check the manifold all by itself later by using the same blocking plate + gasket.

I did this using an old blocking plate and gasket when I checked my 454 manifolds.....putting the blocking gasket on each manifold and using the riser as the "plate".

THEN, I pressurized each manifold to 20psi and both held all day!

Some use acetone to test manifolds but the only SURE way to pressure test a manifold is with compressed air. It's just a little harder to get a good seal when using a blocking plate on the riser surface.

Risers on the other hand are a little harder to pressure test since there's no flat surface to easily seal on the exhaust since cooling water is "mixed" with exhaust.

This is where you might seal the flat riser surface, stand it upright and fill it with acetone. Then look carefully for cracks inside the exhaust port. The acetone will leak through those cracks and the area leaking will appear "wet" as the acetone seeps through......

Risers also don't usually crack due to freezing, since they drain quickly after shutdown. They more often leak due to "rust-through" ........ If I have a really rusty riser, it's old, and the passages are nearly blocked with rust, I just replace it.

I wouldn't waste time trying to clean it and check for leaks......and although some have had some success doing this, it's dangerous because there's no sure way to know when the riser finally rusts through enough to leak........ until it does......

And if that's before it's shut down after winterization, and that water ends up in 1 or more cylinders, it will be wet in there for the entire winter and a rusty mess by Spring.

Long winded answer....sorry about that. Just disconnect the exhaust manifold and plug it's supply hose from the engine.

Cheers,

Rick

 

[Jon1229]

Couple of ways you can do it.

One way is to make up a metal plate (with a homemade gasket)....... remove the elbow and seal the exhaust manifold using the gasket and plate, then you can pressure check the manifold along with the block and head.

But, normally, you want to isolate the manifold and riser from the engine block/head(s). Since manifold leaks don't really result in a LOT of water in the oil, you only want to pressurize the head and block.

The manifold is usually only connected to cooling water via a 5/8" or 3/4" hose etc anyway, so it's much easier to just disconnect the manifold water supply altogether from the cooling system and plug the hose with a suitable plug.

You can check the manifold all by itself later by using the same blocking plate + gasket.

I did this using an old blocking plate and gasket when I checked my 454 manifolds.....putting the blocking gasket on each manifold and using the riser as the "plate".

THEN, I pressurized each manifold to 20psi and both held all day!

Some use acetone to test manifolds but the only SURE way to pressure test a manifold is with compressed air. It's just a little harder to get a good seal when using a blocking plate on the riser surface.

Risers on the other hand are a little harder to pressure test since there's no flat surface to easily seal on the exhaust since cooling water is "mixed" with exhaust.

This is where you might seal the flat riser surface, stand it upright and fill it with acetone. Then look carefully for cracks inside the exhaust port. The acetone will leak through those cracks and the area leaking will appear "wet" as the acetone seeps through......

Risers also don't usually crack due to freezing, since they drain quickly after shutdown. They more often leak due to "rust-through" ........ If I have a really rusty riser, it's old, and the passages are nearly blocked with rust, I just replace it.

I wouldn't waste time trying to clean it and check for leaks......and although some have had some success doing this, it's dangerous because there's no sure way to know when the riser finally rusts through enough to leak........ until it does......

And if that's before it's shut down after winterization, and that water ends up in 1 or more cylinders, it will be wet in there for the entire winter and a rusty mess by Spring.

Long winded answer....sorry about that. Just disconnect the exhaust manifold and plug it's supply hose from the engine.

Cheers,

Rick

Update. I’ve pressurized the block to 15 and it’s been holding at 15 for an hour already, going to wait a few more hours before jumping to any conclusions. When pulling the spark plugs I noticed that #2 had corrosion and #4 had pure clean oil on it not milky oil like the oil seen in the dipstick and inside the valve cover.

 

[Jon1229]

Pulled valve cover and now I can see that there looks like a burn mark on the exhaust manifold gasket, and it looks like there is a little space where air/water could enter/exit.

 

[Jon1229]

There was also oil completely covering one of the bolts that fastens the manifold to the block

 

[Jon1229]

Block held pressure for 6 hours now, hasn’t even gone down 1 psi. What do you guys make of the pictures I posted?

 

[tank1949]

No disrespect but I didn't read throughout all the responses, but if this motor has been saltwater cooled for 17 years, replace it. If not, find a better mechanic with tools to make sure both heads and block are FLAT!!! I bought a reconditioned automotive 5.7 v8 head one time that had a defective OVER LARGE water passage dangerously near combustion area. I took shop's word it was OK! Shame on me! My motor locked up over the winter months, regardless of flushing it. When ANOTHER machine shop rebuilt motor, he showed me how water had intruded. I know what u are going through!!!!!!!!!! Head gaskets are supposed to be keyed so that there is only one way that they will fit. "Supposed to be" If so, and you have torqued correctly, head or block is not flat. Or, someone sold u the wrong head or gasket. Good luck!

 

[HT32BSX115]

Block held pressure for 6 hours now, hasn’t even gone down 1 psi. What do you guys make of the pictures I posted?

Pretty hard to tell anything by the pictures. Water is evidently not entering the crankcase via the cooling system and there should be no path between the manifold and block. Cooling water is ported to the manifold via a hose.

I didn't see if your engine is a salt water engine, but if it is, your pressure check verified that the block and head are not leaking water.

You need to ensure that you have gotten all the water out of the pan. Either drain it from the bottom of the pan or use a suction pump.

The put clean oil in it and run it like you stole it for an hour or more at cruise or higher power setting. make sure your T-stat is installed to get it up to max temp.

 

[Jon1229]

Pretty hard to tell anything by the pictures. Water is evidently not entering the crankcase via the cooling system and there should be no path between the manifold and block. Cooling water is ported to the manifold via a hose.

I didn't see if your engine is a salt water engine, but if it is, your pressure check verified that the block and head are not leaking water.

You need to ensure that you have gotten all the water out of the pan. Either drain it from the bottom of the pan or use a suction pump.

The put clean oil in it and run it like you stole it for an hour or more at cruise or higher power setting. make sure your T-stat is installed to get it up to max temp.

Will do. So the test basically ruled out the head gasket, head bolts not being sealed properly, and a crack In the block/head? And a bad manifold gasket shouldn’t introduce water into the oil? Thanks for all the help it’s appreciated

 

[achris]

Will do. So the test basically ruled out the head gasket, head bolts not being sealed properly, and a crack In the block/head? And a bad manifold gasket shouldn’t introduce water into the oil? Thanks for all the help it’s appreciated

Correct. How does the exhaust elbow and it's gasket look? The other possibility is a cracked manifold.

 

[Jon1229]

Correct. How does the exhaust elbow and it's gasket look? The other possibility is a cracked manifold.

The elbow gasket had some rust stains on it so water may have been leaking somewhere. I’m picking up a new elbow gasket and manifold gasket tomorrow, but how would the manifold crack in the middle of the summer? There was no water in the oil from may till the end of July