water in oil OMC 351W..what do I look for?

[danthern]

Hey Guys....I have water in the oil in my 77 OMC 235 hp 351W. Took it to the local marine place. they performed a compression check which was normal, but they said that a plug on one side was clean, indicating that water was washing it off...??? They say its either a blown head gasket or a cracked block. I'm tearing it down in a couple days, and need to know how to pinpoint my problem. i assume I'd be able to see a place on the head gasket where water is getting in..?? On the heads I assume I should look for cracks at the ports. if present, will they be pretty apparent? Same thing with the block...where should I look for cracks? I'm also told that manifold/ riser leaks can cause the problem....how can you tell if thats the case?<br />thanks for any suggestions.<br />Dan

 

[stub756]

Re: water in oil OMC 351W..what do I look for?

What did the compression test read.. I may be way off but id think if compression checked out ok go look at the manifold and riser... Your exhaust door might be gone and your boat may have ingested water. If you had a leaky Head I'd think compression would read lower and same with a crakced block.

 

[Bart Sr.]

Re: water in oil OMC 351W..what do I look for?

danthern---I have seen posts here suggesting that pressure testing manifold and riser before pulling the head(s).Then if you do have to pull the head(s) you should have it(them) magnafluxed to locate cracks/leaks.<br />Good luck.

 

[danthern]

Re: water in oil OMC 351W..what do I look for?

Thanks for the help guys....I'm not certain what the results of the compression test were as far as the numbers go, will find out Mon. when I pick the boat up. It is encouraging that maybe the block is ok....when you say the "exhaust door" pertaining, I assume, to the manifolds and risers, I have to admit that I don't know what you mean. Can you elaborate?<br />Thanks a million,<br />Dan

 

[Bart Sr.]

Re: water in oil OMC 351W..what do I look for?

Exhaust door=flapper.

 

[Bondo]

Re: water in oil OMC 351W..what do I look for?

Dan,<br />Go to the top of the page,+ Click on Manuals...... Find 1 for your Engine/Outdrive....<br />It's Alot Easier to Help you out, If we All speak the same lingo..... Besides You'll Learn Alott from a Manual.....<br /><br />A Good Compression Test rules Out the headgasket.... Cracks can be very hard to see, Sometimes.... Other times it's Very Apparent... Keep looking for Rust....

 

[danthern]

Re: water in oil OMC 351W..what do I look for?

Thanks fellows....I do have a shop manual, I'll refer to that. I'll keep ya'll posted. This site is great!! Thanks again.<br />Dan