View Full Version : Water in oil

Billy Oconnor
07-26-2002, 08:30 AM
" Help !!!! I have an 1987 Four winns with a 4.3
I just discovered while changing the oil that i had about 8qts of a milky oil. The engine is not skipping and the plugs are dry. So where do i start checking and what type of test can i perform ??? I have heard this could be a cracked block ,head gaskets , intake manifold leak or manifold flappers. Any help would be great.
thanks Billy "

07-26-2002, 07:06 PM
"All of the things you listed are possibilities, but if the plug deposits look normal and uniform, it's probably not a cracked head or bad head gasket. If it has the original exhaust manifolds, I'd replace them - they're 15 rusty years old anyway and one of the most common sources of water getting into the engine.

The next most common thing is a cracked block due to freezing. And this all assumes water didn't back up the exhaust and get past the risers.


07-30-2002, 01:43 PM
" Billy,

I hate to tell you this, but you should assume at this time your going do a teardown or replacement on that engine. The only diagnosis that doesn't immediately require a teardown is manifolds and the fact of the matter is that there isn't any convenient way for water to get from the manifolds to the oil pan without doing other serious damage along the way. Further, a lot of water in the oil does bearing damage almost immediately. The safe thing to do for touble free boating is to put in a long block now.

Things you might do to try to save the engine:
Were there any metal fragments in the oil you drained? This indicates bearing damage. If you still have the old oil, send out a sample and have it analyzed.
Do a compression test. A blown head gasket or broken piston will show up as low compression on one or more cylinders.
Once you have isolated the source of the water and repaired it, and the compression and oil look good, run the engine for a short period and replace the oil again. Get all of the water out. I recommend draining from the oil pan drain plug if you can get to it to get all the sediment out of the oil pan.

Good luck! Stay close to home till your sure you can trust the engine. "

08-01-2002, 04:23 PM
" I slighly disagree with the requirement to tear down the engine, at least - not yet. If it is running fine, you might be OK. The most likely cause of the water in the oil is a leaky riser gasket or rusted exhaust manifolds and risers. First I suggest closing the raw water input, close the fuel valve or disconnect the input to the fuel pump. Disconnect the lead from the ignition coil. Remove all the plugs. Drain the contaminated oil from the engine. Add new oil (it's OK to use a generic brand), some people suggest a 50/50 mix with kerosene and that's OK also. Shoot the cylinders with a healthy dose of Marvel Mystery oil or CRC. Give a healthy dose of the same into the carb as well. Crank the engine. Repeat draining the oil and lubricating the cylinders until you are certain all the water has been removed. Refill the crankcase with manufacturer suggested oil. Check your compression. It it's good - smile and press on. If it is bad or 2 adjacent cylinders read exactly the same, you might have a bad head gasket or cracked head/block. If your compession isn't right, you probably have to do at least a partial tear down. If the compression is good press on and remove and check you risers and exhaust manifolds. You might only have a leaky gasket between the riser and manifold. Replace everything you suspect as faulty. Check and/or replace the exhaust water shutter. Reassemble, open the sea cock, turn on your fuel and hope for the best. After the engine has been at operating temp for about 15 minutes, drain and refill the oil again to remove residual water.

Later "

Chris Dawson
08-02-2002, 09:24 AM
" I have just acquired a 1985 correct craft with a 351 ford windsor engine. The engine runs but there is water in the oil , do I follow the same advice for this engine and is there anybody who would be able to tellme how to get hold of a works manual to show me what to do

Many thanks

Chris "

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Jim Hall
09-02-2006, 09:32 PM
"I had a water pump and impellor failure. Engine overheated and blew head gasket. Did the gasket and after 2 oil changes, I still have water in my oil. Head was milled and magna fluxed? Mechanic said all was well. The engine is a 3.0 L Mercruiser. Compression showed 175, 117, 175, 175. After re-adjusting vaves on #2 cyl., compression was at 172. Did valve being open suck water into cylinder? Haven't checked the manifold or riser yet. All cyl.'s were dry except #2. Kinda lost, any help would be greatly appreciated. TIA [email protected] ("")"