Water in oil

"I have a 1985 Mercruiser 140

"I have a 1985 Mercruiser 140 4 cylinder. End of last season I noticed water had got into the oil making it milky. It was ok all season but the last time it ran I noticed the water in the oil. It is always winterized correctly each season. I've owned the boat for 10 years. I originally thought the intake/exhaust manifold was cracked and leaking so I replaced it with a new manifold & gaskets. It evidently was not the problem. The head was also replaced around 5 years ago and a new camshaft a few years ago. Changed the oil and ran engine for 10 min or so and water showed up again. The engine runs good without cutting out or missing and has not been overheated. I don't believe the head is cracked, but will remove it to check. I have been told that the head gasket is the main concern. Any input on other possible causes would be appreciated!"

If there is no water coming ou

If there is no water coming out of the spark plugs you have a lower engine problem; cracked block comes to mind. Perform a compression test both dry and wet after the engine is warm. Head gasket may be cracked between the water jacket and a cylinder. Hot engine water in small amounts will vaporize and actually burn. A very clean plug is evidence of it. Compare the color of all your plugs. They should all be med. brown to tan if the engine is running at optimum efficiency. White plugs are from a too lean carb. Black sooty plugs are a rich carb condition. Black oily plugs are from bad rings or worn valve guide seals.

You can pressurize the block water jacket to see if it is not cracked.

"I haven't begun tearing i

"I haven't begun tearing into yet, but if it happens to be a crack in the block, would it be most likely visable? If the problem is the block, is the block repairable or does it have to be replaced? If it has to be replaced, any suggestions on where to locate a replacement or should I consider replacing the engine with a rebuilt long block if they are available for the same year and setup I currently have? I'm not sure if my older 1985 model is available or if I would have to upgrade to a more current 4 cylinder?"

"pressure test the cooling sys

"pressure test the cooling system, before you run through all the "what if"'s"

"I removed the head from the e

"I removed the head from the engine. Just doing a visual inspection I didn't see any cracks in the head or on the block surface where the head mounted. The head gasket didn't show any obvious blow out areas or obvious signs of leaking. When breaking loose the head bolts I did notice a few seemed easier or looser to break free. As of yet I have not cleaned the head off yet. The only obvious thing that I noticed was that cylinder #2 looked like it had been wet or getting water in it. The exhaust port on that cylinder looked different from the others in that it did not look greyish like the others and looked more similar to the intake ports in that it looked like it had been wet or darker similar to the intake ports. The piston top looked different for this cylinder too, like it had been washed or cleaned slightly compared to the other pistons. The engine has not been ran much in this condition so the leakage point may not be very obvious. Does anyone have any ideas or can tell me how to inspect for possible problems that are not visible after initial inspection? I do plan on cleaning the head thoroughly and the block as good as I can and inspecting better. I also checked the flapper in the exhaust and it looks ok after being replaced only a few years ago. I didn't try a compression test because after reading similar posts it sounded like most of the problems could be found after removing the head. Any help or suggestions would be appreciated."

"you took the head off before

"you took the head off before pressure testing? you're shooting fish in a barrel now....
I recommend a new head gasket, put it back together and then start over by pressure testing the cooling system.
Probably a failing exhaust manifold.
I don't know what posts say problems are solved removing the head, but that seems out of order to me. You only remove the head after a diagnosis tells you to. "

"cylinder #2 looked like i

"cylinder #2 looked like it had been wet or getting water in it. The exhaust port on that cylinder looked different from the others"

Sure sign of an exhaust manifold and/or gasket failure. Pressure test it or replace it.

Clean out the head bolt holes in the block and use a THREAD CHASE on the threads to clean them. DO NOT USE A TAP ON THE THREADS. Do the same for the exhaust manifold bolt holes.

Check your manifold and block mating surfaces w/a straight edge.

"I just replaced the exhaust/i

"I just replaced the exhaust/intake manifold with a new Barr manifold # 1-99798 and new manifold gaskets, bolts, nuts etc. Also cleaned riser and new gaskets & hardware. I replaced the manifold because there was a visible outside crack. I originally thought this was the cause of the water in the oil. After installing the new manifold and new oil & filter, water was still getting in the oil. I put a straight edge on the head already and it appears to be ok. I will do the same with the block and clean all the parts to be reassembled and install with new gaskets. I've never done a pressure test before. Is there information on the procedure somewhere or can someone give some pointers on how to? I think I already have a cylinder pressure tester (spark plug type) somewhere. I will thoroughly clean, inspect and reassemble with new gaskets and see if that is the fix unless I can get some other ideas of what to check out. Any other input is appreciated.
Thanks!"

Did you remove the head or the

Did you remove the head or the valve cover?

If you are capable of this kind of mechanical engine work..............
IF you did remove the head look very closely at the head gasket. Look at the water passage holes and inspect very closely and see if the water hole areas have bled into the cyclinders.

Also when water gets into the oil and it gets mixed well it takes 3 - 4 oil changes ( after running each time) to get most of the water out of the oil system and then there is allways some risidual for a while.

Also it sounds to me as if this motor was NOT winterized properly. If the exhaust manifold cracked there is a 100% chance the block did also!!

You may be looking at a new motor instaed of throwing good money away on a bad one. I would do some reaserch online if this is the case and see what a 4 cyl short or long block (rebiult) costs.
You may be able to get out of it for ~ $1000 or so. I know a rebiult marine small block V8 (long block goes for ~ $1500- $1700 around here. Not sure on the 4 bangers!

"Yes, I removed the head. I ju

"Yes, I removed the head. I just replaced the manifold the day before so the job of re-removal was very familiar and removing the head wasn't much more work. The crack that was visible on the old manifold had been there for years. I'm not sure that was even the cause of the water leak. I just thought that it finally got to the point where it started leaking water into the oil. When I winterize it each season, I drain the water from the manifold and block drains and then add a gallon of antifreeze thru all the water hoses, disconnecting then reconnecting after filling. The head was replaced early after I bought the boat due to cracking from overheating because the water impeller in the outdrive was bad. I had a new cam put in it 2 years ago, but I didn't do the work on that job.
I'm hoping that maybe it was just the head was working loose. It popped loose after all the head bolts were loose and didn't take any persuading to get loose. To me, and I'm no expert, but it looked like only the #2 cylinder was getting exposed to water. I will have to do more inspecting after I have a chance to clean everything up better. I just did a initial inspection with oil still on everything since it was about 9pm and it was dark and it was time to stop until I got some more information and could see things better.
Unless something shows up after further inspection or someone can suggest other possible problems, I will reassemble if I don't find anything, with new gaskets and a thorough cleaning and run thru some new oil 2-3 times and see if the water clears out. If not, I know something else is wrong, possibly out of my range of abilities to fix myself.
I've considered a new engine several times with different problems over the years. Everytime something breaks down I always think I should have sold the thing while it was running good, but that is when I enjoy having it...

Thanks for all the info and suggestions and any further input."

"Mike;
My nickle's worth:

"Mike;
My nickle's worth:
It may be time to consider a complete repower package bellhousing forward.
This would get you all new everything and buy you a few years of peace and reliability.

The trouble with boats much over 20 years old (an arbitrary number) is that they start to two bit you to death. One day its a new starter, 2 weeks later its a new water pump, then a month later new carb, or whatever. This can make you crazy.

Rod"

"Believe me, I have seriously

"Believe me, I have seriously thought about a new engine. With all the repairs I have done over the years I think I have paid for the boat twice!

Is there a reasonable place I could find a new engine or long block that would be close to a direct replacement or minor conversions?"

"First I would check this site

"First I would check this site.
There is also Michigan Motorz, and Jasper Engines seem to be reputable suppliers.
Others here will chime in with their favorites also I hope.
I repowered last year with a Merc package, but this sure was not the most cost effective way to go.

You can get long block packages and bolt on all your old accessories, but if their history is uncertain, you might wind up with more issues. I think a better idea is complete drop in package, then you know where you are at; but it costs more money.

Rod"

"Thanks!
One other main point

"Thanks!
One other main point that needs to be taken into consideration is that this first showed up at the END of the season last year before any freezing temperatures. So I don't think freezing could be the cause unless it took all summer to finally start leaking. It ran great all summer until this & still does, just with water in the oil. I didn't bother working on it until recently since the mississippi was shut down from flooding part of this season and gas is so high.
Do sailboats have all these problems???"

"Sailboat are more reliable, b

"Sailboat are more reliable, but they go too slow and they don't sound good."

"I haven't been able to ju

"I haven't been able to jump back into my problem just yet, but after I get everything cleaned up and if I don't find any obvious problems, I will get new gaskets, reassemble and see if that fixes the leak.

Still would like some help on how to do a pressure test if someone wants to offer how to do the procedure.

I have also been researching the option of a new or remanufactured base engine. From what I have found, it sounds like it will only take a few modifications to get a replacement to work. Sounds like the engine supplier says I would need a 12-3/4" flywheel and possibly a updated coupler. How do you determine if you need the new coupler? They said I could return it if it wasn't needed. I also looked on some marine part sites and noticed they offer a flywheel ring gear with 153 teeth for 12"-12-3/4" flywheels. Just wondering if I could save a little money if I can just replace the ring gear on my existing flywheel? They say the replacement engines ship with 14" flywheel and would not work with the current flywheel housing and starter. Does anyone know of any other modifications I would have to do if I go with the new base engine? I don't want to get too deep into replacing every little thing here and there just to get it running again. I'd like to try and get the job done in one shot. It sounds like the replacement engine is going to be around $2000 with shipping and needed modifications."

Go to a plumbing center and ge

Go to a plumbing center and get a rubber drainpipe plug to fit the water intake. I looked at a diagram of the T'stat hsg. and was not able to see it clearly but I would use a piece of bicycle tube w/air valve between two water connections and pump 15 lbs. into it. The object is to close off all water ports to/from the engine and add air pressure to it. Close of water to the exh. man.