Mercruiser 3.0 water in oil

[osavchuk]

Hello everyone, I hope everyone is doing great.

I have a boat 1994 Regal Valanti 176 SE. The boat has a 3.0 MERCRUISER SN#F077854. It is NOT a closed-loop cooling.
About 2 years ago my impeller shredded and I overheated the boat. Smoke was coming out of the engine bay like crazy, fried exhaust elbows and shutter.

A week ago replaced all the exhaust elbows, water shutters, water pumps, thermostats, and flushed a system by connecting a water hose to both of the hoses at the thermostat, replaced all the bellows. I started the boat on earmuffs and ran it times for a few minutes while adjusting timing. When I checked the oil after dipstick shows 3 times as much of milky white oil.

Tested compression:150 each cylinder.
NOTE: Before I started to work on the boat I checked the oil, it was nice and brown at a normal level.

I have read a lot about this issue on this forum, could be cracked warped head, bad head gasket bad cracked block lost of different issues.

Where can I start tracing this problem?
Is it possible that when connected the hose to the said input and output of the thermostats assy I somehow introduced water into the block?

Thank you all in advance.

 

[Scott Danforth]

first, drain the water
second pressure test the cooling jacket and listen for the leak

most likely you either A.... fried the gasket between the manifold and riser, B, fried the head gasket and left the fire-rings intact (highly unlikely, however plausible) or C... cracked your block or head.

 

[osavchuk]

I can pressurise the cooling jacket? I though it was only on closed cooling systems. If the gasket between manifold and riser is bad it will let water back into the block? Also, bad head gasket would indicate low compression? Or not always. Thank you

 

[Scott06]

I can pressurise the cooling jacket? I though it was only on closed cooling systems. If the gasket between manifold and riser is bad it will let water back into the block? Also, bad head gasket would indicate low compression? Or not always. Thank you

Yes block of water supply and discharge to exhaust manifold supply with compressed air. If gasket between manifold and riser is bad you get water in the Cylinders , typical 3&4 on your engine. Eventually you get water in oil this way or hydro lock.

typicallywould expect bad head gasket to have low compression but you got the engine really freaking hot so may be leaking water into oil and not loosing compression. When you pressure test listen for where air pressure is coming out - oil fill or intake or exhaust. You may have cracked the head or block if it got that hot, or may have freeze damage. If there is that much water on the oil you have a big crack most likely

 

[Lou C]

Yeah I had the same thing happen. Bad overheat but no water in the oil and ran fine for 2 more seasons. Then at the end of the 3rd season blew both head gaskets; water in a cyl and water in the oil. However normal comp test results. Found combustion gas in the cooling water. Took it apart saw blown HGs. Had heads checked and machine shop found that the center cyls of both heads has cracks in the exhaust valve seats. Shop advised replacing with reman heads which is what I did.

 

[osavchuk]

Thank you Scott,
Any suggestions as to how many PSI and which port would u recommend I supply compressed air to?

 

[Scott Danforth]

15 psi

pull hose from transom shield and hose going to exhaust. put a tee in a new hose, install the hose with a tee between the nipples that you just pulled the other hoses off.

 

[osavchuk]

So, I have rigged a couple of hoses and check valve, drained all the water and applied 20 psi, my pump gauge is off by 5 psi. Tried to find the leak and nothing, the pressure is holding and only dropping 0.5psi every 15 minutes. It could be that ever time I check using digital handheld tire pressure meter I lose some air?
Should I test the same way exhaust/ intake manifold and riser? I can make a steel plate and some gasket material to cover exhaust at the elbow.

 

[osavchuk]

Update, used soapy water and discovered small leak around the thermostat hose, torque it a bit more, applied 15 psi. Checked pressure after 2 hours was still sitting at 15 psi. Does this mean my block and my head are ok? Can a bad exhaust manifold gasket also introduce water into the block?
Thank you all.

 

[Scott Danforth]

if you are holding pressure in the water jacket, then you can rule that out

pull your manifold and focus there now. you most likely have an issue at the manifold to riser joint or a crack in the manifold

 

[osavchuk]

Hello everyone,
So, I have made a steel plate and gasket for the riser and plugged covered it up. Installed a hose on to a exhaust manifold with a shrader valve, pumped 20 psi into a manifold. So far so good, holding 20 steady for the past 25 minutes.
Does this mean I am all good ?
If riser gasket was bad, and water got in via bad riser gasket, how could have this water end up in my block in oil? I just dont get it.
Also, I have originally stated that I had 3 times above oil stick level, it was actually twice as much. That would equal to additional quart.
Thank you all

 

[Scott Danforth]

if it was the exhaust elbow gasket, water would run down the exhaust manifold and run into cylinders 3 and 4 if it came in from the exhaust.

if you pull the manifold, or use a bore scope, you would see rust trails.

1 quart of water in the motor would cause a foamy/frothy mess that would come out the breather on the valve cover. actually, only 6 ounces of water are required to cause that much foamy mess.

could it be fuel in the oil?

 

[osavchuk]

So, if water makes it's way to the cylinder 3 and 4, how does it than enters a block?
Would into just hydrolock or something? Cylinder 3 plug was exceptionally clean compare to others that were black.
No rust on plugs, they are new.
Fuel in the oil, hmm interesting. I have just rebuild a carb, readjusted the float. Would that mixture creat milky white oil? Which became thicker actually.

 

[Rick Stephens]

So far, all the likely suspects appear negative. Gas in the oil will just thin the oil, and make it smell. It will not make it foam.

A little water in a cylinder will burn off all the carbon and make a plug look clean. Definite sign of water. Water in a cylinder can cause hydrolock, or, if let sit, will drain down through the rings into the pan. Running it won't get through the rings. I get the impression that you had a fresh oil change and fired up and got a lot of water in the oil. That said, it is either a crack (internal or manifold), a bad exhaust to riser gasket, or a head gasket. Sure seems like when only running on muffs the issue would have to be internal to the engine and not manifold sourced. The exhaust on muffs should carry a manifold leak out the back.

BTW, get all the water out soonest so it doesn't cause more damage.

I'm back to thinking head gasket. Clean up and change the oil and run again. Check compression after warming.

 

[osavchuk]

Assembled everything back together. Replaced riser gasket. Added cheap 10w-30 just to wash out water, starter, and ran it for 10 minutes in idle. Checked the oil, level of the oil did not change, it still has some water in it, not as much kinda mixed in there, guessing from what was left. How many times should I do the flushing?

Is it possible:
I overheated the boat about 3 years ago, it sat for 3 years half the time not covered. The motor was covered with just a hood.
When I started to mess with it again discovered the carb was all rusted out bad. The fuel pump was new 3 years ago was rusted so bad it would not even work. I cracked it open the fuel pump, rust was everywhere. Fixed all that. That is when I checked the oil and it was not milky. Cranked the boat a few times and started it.

Is it possible the water was sitting under the valve cover or elsewhere and when I started it just slipped into the case?
Or maybe my oil was always milky, just not mixed yet, and when I pulled the dipstick it was fine for just that one moment and when I started the boat i mixed all the water with oil?

 

[Rick Stephens]

Assembled everything back together. Replaced riser gasket. Added cheap 10w-30 just to wash out water, starter, and ran it for 10 minutes in idle. Checked the oil, level of the oil did not change, it still has some water in it, not as much kinda mixed in there, guessing from what was left. How many times should I do the flushing?

Is it possible:
I overheated the boat about 3 years ago, it sat for 3 years half the time not covered. The motor was covered with just a hood.
When I started to mess with it again discovered the carb was all rusted out bad. The fuel pump was new 3 years ago was rusted so bad it would not even work. I cracked it open the fuel pump, rust was everywhere. Fixed all that. That is when I checked the oil and it was not milky. Cranked the boat a few times and started it.

Is it possible the water was sitting under the valve cover or elsewhere and when I started it just slipped into the case?
Or maybe my oil was always milky, just not mixed yet, and when I pulled the dipstick it was fine for just that one moment and when I started the boat i mixed all the water with oil?

Nope. However, I was gonna ask if it was possible the carb was left open. If the crankcase got water drained down from rain, it would just show as a little over full. Oil and water won't mix just sitting and the oil will wipe off the water as you pull the stick out. RUn it, and the water foams up and makes a mess.

Get the motor nice and warm and run it for a bit. The little water left in it will either boil off or emulsify in the oil. Change it afterwards and you'll be in pretty good shape. Good test too. If the level goes up, you know you have a leak somewhere.

Rick

 

[osavchuk]

The carb had an arrestor on it, the choke was closed. The motor was covered with a hood, could have been leaking inside. It's Florida the humidity here unbearable sometimes.
When I opened the choke I could not see the bottom rust covered the entire opening, so not sure if direct rain got to it at one pint or just lots of condensation. I have never seen as much rust in the carb or fuel pump.

I will refill with good oil and report back.

Do you by any chance know why I cannot open water on full if its on ear muffs? Am I introducing to much water?

Thank you

 

[Rick Stephens]

Should open water faucet to full on muffs. The impeller will only take in what it needs at any given RPM and spray out the rest. Don't run over 1800 RPM on muffs or you'll suck the hose dry.

 

[Searay205]

the problem is your manifold may be corroded through. the hot exhaust gases hit the manifold on the other side is water. It corrodes/erodes. Pull intake/exhaust manifold on that engine they are integrated. look in all the exhaust ports and you will probably see a hairline crack, they will be paper thin if older than 5 years.

Everyone screams head gasket and everyone is wrong. that old iron duke is almost impossible to kill unless you fill it with water.

 

[osavchuk]

the problem is your manifold may be corroded through. the hot exhaust gases hit the manifold on the other side is water. It corrodes/erodes. Pull intake/exhaust manifold on that engine they are integrated. look in all the exhaust ports and you will probably see a hairline crack, they will be paper thin if older than 5 years.

Everyone screams head gasket and everyone is wrong. that old iron duke is almost impossible to kill unless you fill it with water.

Thank you Searay205 for your advice, I have pumped 20psi in there on the exhaust side and it held pressure well. Wouldn't it let air out into a block?