omc cobra 3.0 water in oil and spark plug holes

[2thmaker]

Hi,

I have an 89 OMC 3.0 Cobra (GM). Last year, I had my boat winterized at a dealer, no water in oil but was told that I had an external engine block crack because they noticed a couple of "streaks of water" coming from under the exhaust manifold. Took boat to same dealer, they said they took off exhaust manifold and it was only a bad gasket which they replaced. They then called and said that now i have an internal crack because there is water in the oil. I went to pick up boat and asked if they tested anything else, they said no and that water in the oil was an indication of an internal engine crack. I have seen on the internet that this could be a blown head gasket, a plugged exhaust riser or a cracked exhaust manifold. I took off the exhaust elbow and it looked okay to me, did a compression test and when it was turning over I had lots of water squirting out of number 4 cylinder. Any ideas? Could it be a cracked exhaust manifold or cracked head? Thanks ahead of the time for any help
Greg Edwards
Tennessee

 

[Bondo]

Re: omc cobra 3.0 water in oil and spark plug holes

Ayuh,.....

It Could be about Anything......
It also Sounds like your Marina is Screwing you.....

Isolate the Cooling System of the Block, from everything else,...
Then add Air Pressure....
You'll Hear where it's Leaking....

 

[2thmaker]

Re: omc cobra 3.0 water in oil and spark plug holes

I took it apart before reading your post, I can't find a crack in either the head or the exhaust manifold. No blown head gasket. Here's a thought, the oil in the water was not there until after they replaced the exhaust manifold gasket, it looks like the exhaust manifold still had some old gasket material on it. Is it possible that there was enough space between the old gasket and new that it was leaking into the cylinders? I'm going to call tomorrow and see if I can have a place check the heads and the manifold for any cracks. Would a machine shop be able to magnaflux or something to check this? Thanks

Greg

 

[Coors]

Re: omc cobra 3.0 water in oil and spark plug holes

Old gasket/ new gasket, yes. Take it back. crap job.

 

[gooders]

Re: omc cobra 3.0 water in oil and spark plug holes

Totally agree, if the engine inlet gasket faces have not been cleaned and rubbed free of any debris then any attempt to fit the new gasket will be floored.I have the same engine 3.0L Cobra and I recently fitted a brand new manifold and elbow, ordered the part direct from Boat Bandit New York (I live in England). Very straight forward job to replace manifold.Dont be too quick to haul your boat to the shop, have a go yourself you may be presently surprised.One tip, be methodical and take your time.

 

[2thmaker]

Re: omc cobra 3.0 water in oil and spark plug holes

Thanks so much, do you know how to test the manifold and riser for leaks, cracks. I don't see any on them, I may try to see if I can figure a way to rig up something to pressure test manifold this weekend before putting everything back on. Did you have water in your oil also? Thanks again
Greg

 

[Coors]

Re: omc cobra 3.0 water in oil and spark plug holes

search old threads, Bondo has a good pressure test.

 

[2thmaker]

Re: omc cobra 3.0 water in oil and spark plug holes

Here's a new thought, let me know what you think. The reason that they removed the manifold was because there was a couple of leaks coming from between it and the head. The discovered that there was a couple of bad spots on the manifold gasket. What if the manifold was getting plugged up and the gasket was a relief (a place to blow out to release back pressure), then when the new gasket was replaced, the manifold ended up cracking at that point? I only started getting water in the oil after new gasket was installed. What do you guys think? Also, apparently my manifold isn't produced anymore, will any 3.0 manifold work on my engine, as a reminder it's an 89 3.0 Cobra. Thanks again
Greg

 

[1969novamarine24]

Re: omc cobra 3.0 water in oil and spark plug holes

There is nothing coming out of your head to the exhaust manifold but exhaust.The gasket between the 2 will not let water in the engine.If the riser gasket is leaking this could let water run back into the engine once the engine cut off.