I have mentioned on here a couple of times before that I am starting to see a little water in my oil. Here is what I think I have going and want to see what you guys think.

Oil pressure is good. About 50lbs at idle, about 65lbs at run speed.

If I run the boat for a good length of time get the oil up to temp I don't see any water at all in it.

Compression in all cylinders is good.

I am thinking about having a leak down test done when I have the boat winterized. I think the problem is a bad riser or gasket.

Any takers?

By the way...the motor is a 502 MPI.

Buck
#183

Buck,
This one is touchy. Usually when an exhaust riser is leaking you will have moisture in the valve covers and breathers. Also, if the riser was leaking bad or the manifolds were leaking you would have signs of water on some of the spark plugs and maybe even water in a cylinder and the engine would be hard starting. If its alot of water the engine may even not crank over do to so much water in a cylinder.
Now, depending on the year, you might have an intake manifold leaking under the thermostat housing, the intake usually rots out.( famous on smallblocks ) Could be leaking at the crossover on the front of the intake or even the rear of the intake. I have heard of oil coolers leaking, but oil pressure is usually more than water pressure, so that may be out. How was it winterized last year? Is it possible that it froze and broke the block open in the lifter valley? Just a thought.
you may want to even eliminate the thermostat housing and block it off and remove your circulation pump hose and put pressure in there. Go to about 30 psi and see if it drops off any. You can use a hand pump with a gauge or a leak down tester with a gauge. This test will tell you if the block is leaking any way.

If you need help with this feel free to call.

Pwrbt33- John
Lead Technician for Service Dept.
Offshore Performance
410-827-0200 x-1

The boat was winterized by a local Marine Mechanic that has been in the area for over 20 years. It was my understanding that he drained everything, put antifreeze in it, fogged, and fuel stabilizer. There may have been more, don't know for sure.

I might add that the oil level isn't going up any. Just seeing a carmel color instead of clear oil. I am running Mobil 1 15w-50 and changing every 20-25 hrs.

I will let a mechanic do the leak down test. How much should this cost?

John...Thanks for the reply, I may call you.

Buck
#183

dont be fooled by an oil cooler leaking, ya, i know oil pressure is always more than water pressure, but had one this year that had a problem on water in oil last year. i built the guy a new engine, with new headers and guess what? after running for about 30 min, i started noticing oil was getting discolored. finally put a new oil cooler on it, telling myself that this wouldn't fix the problem. hmmmmmm, gee clean oil from then on. i wouldnt believed it, but saw it for myself.

Dr. Dave,

You are right. Even though the oil pressure is greater, the water still gets in there. I had an oil cooler break once on a customers boat, and the water go into the oil, and even had water comming out of the exhaust because it was being expelled thru the water system.

I removed the cooler, ran the motor without a cooler with some 5W-30 so the oil would heat up and burn off the moisture. Mind you I didn't run the boat, I only ran it on the hose. I did about 3 oil changes with the 5W-30 about every 30min.

I put the new cooler back in and did another oil change, and removed the valve covers and cleaned them. This I put the standard 20W-50 back in and took the boat for a nice 1hr long hard ride to burn off the rest of the moisture.

Thanks guys,
I havent yet seen that problem for myself, but Im glad to know that it can happen all the same. I'll have to keep an eye out for that one !

Thanks again.

Pwrbt33

PS. It depends on how hard your boat is to work on, it shouldnt be anymore than an hour to hour and a half.

If you have a leaky riser gasket you should find some water in the cylinder after shutting down for awhile. Pull the plugs and inspect the plugs looking for water signs then crank it over with the plugs out looking for the spray out of a leaky side. It might be internitent depending on which valves were are open when the motor shut down.

I will go ahead and inspect the plugs before I do anything else.

I spoke to the Marina that will be winterizing it and let them know that I would like to have them do a leak down test. If there is a problem I would like to know what it is before this winter. This way I can have it ready to go by spring.

Hopefully it's nothing that will require pulling the motor and going into it. Just not in the budget right now.

Buck
#183