Gray engine oil 3.0

[jpimentel]

I have a 1987 omc GM 3.0 in my boat that was given to me by a friend. My question is i had about 6 hrs on fresh oil and decided to change it when i could hear my valve train ticking under load. Also had a lot of blow-by, checked compression, all great! The oil i drained looks gray and thin, I don't see any water in it.<br /> Any thoughts would be great!

 

[Don S]

Re: Gray engine oil 3.0

Some types of oil turn milky gray instead of milky tan when it's well mixed with water. But water is your problem.

 

[Bondo]

Re: Gray engine oil 3.0

Ayuh,.............<br /><br />Gray = Water.......

 

[richard99]

Re: Gray engine oil 3.0

Maybe an idiotic response, but could the oil be foaming?

 

[jpimentel]

Re: Gray engine oil 3.0

I thought oil could not mix with water?

 

[QC]

Re: Gray engine oil 3.0

When you run the oil and water in that little blender of yours they can and do stay mixed. It's called emulsification.

 

[jpimentel]

Re: Gray engine oil 3.0

Ok! What would be the first place to check?<br />I would assume the intake manifold, would a vacuume test show a leak, if so how should it be done?

 

[Haut Medoc]

Re: Gray engine oil 3.0

The first place to check would be the exhaust manifolds/risers to see if they are cracked/porous, or leaking at gasket that joins them. Next would be cracked block/head(s)/ intake manifold. A blown head gasket also, but that would most likely cause you to overheat..J

 

[Don S]

Re: Gray engine oil 3.0

I personally don't think a leaky intake manifold or exhaust manifold/riser will get enough water in your oil to make it turn gray. Especially after an oil change, and it being a 3.0L. It would have to leak past the rings at a very high rate, and wouldn't be happening with the engine running.<br />Time to drain the cooling system, block off the hoses for the cooling system to isolate the block and do a pressure check.<br /><br />Is your engine raw water cooled or fresh water cooled (with heat exchanger)?

 

[jpimentel]

Re: Gray engine oil 3.0

The engine is raw water cooled. I have another question, I had pulled off the manifold (front) end plate while the water was still in the manifold, could it have entered this way? The reason i took the end plate off was because someone put the wrong thermostat housing on my boat and was lookin for the thermostat so I could change it. As of now there is no place for a thermostat on this motor, beleive it or not.

 

[Don S]

Re: Gray engine oil 3.0

You may have overlooked where the thermostat goes. It's not the same size as most automotive thermostats, it's a lot smaller.<br />Item 6 in the pic below is the stat.<br />As far as the water, hard to say. Change your oil and filter, and try it again. It may take several changes to get it clean again. <br />It may be well worth the time to pressure test the block before changing the oil a bunch of times.<br /><br />

 

[jpimentel]

Re: Gray engine oil 3.0

The picture that you are showing me is what I should have, it looks the same but it is only one piece, it don't come apart at #13 & #4 I think it's for a closed system? I bought the themostat and expected to put it where the picture shows it but to my surprise (again) it's wrong.

 

[Don S]

Re: Gray engine oil 3.0

You need to order some parts and get your engine setup with the thermostat done properly.<br />Parts of your engine may be overheating because of the rapid water flow, but not showing on the gauge because the only water the gauge sender sees is in the Tstat housing........<br />Not good for your engine at all.