milky oil

[daveofds]

I own a 1976 S2 8 meter center cockpit. The Atomic 4 has served me well as I just need to motor out to the main body of the lake to sail. The only major issue I have had was with raw water cooling and I corrected that. I replaced the impeller which appeared to have melted, loosened and retightend the thermostat housing, replaced a small length of hose, and then my cooling system worked well. Of late however my oil has turned milky gray. From other posts I have deducted that this is from water contamination, but there is also an odor of gas in the oil. I just pumped out the oil via the dipstick hole and changed it. I raised level to full on dipstick and it was clear before I started the engine. Once a ran the motor for a few minutes to get it warm I checked the oil again. It was the same milky gray. I do not have the funds or desire to rebuild this engine if I have a crack that is allowing water from the jackets into my crankcase. I will continue to check to see if the level on the dipstick continues to rise (Indicating further water intrusion?). I also have been led to believe that this may be a fuel pump diaphragm issue. I suppose I could change the oil out again with the engine nice and warm in hopes that I have a residual of gray oil or sludge in the bottom of the crankcase or engine that made the oil turn gray. Any advice?

[edwardc]

After a water intrusion incident, it will take 2 or 3 oil changes to completely clear it out. Just use the cheapest oil you can find for the first 2 changes, as you're only going to be running it a very short time before changing. Save your good oil for the last change.

If you have an aftermarket oil filter, be sure to change it too each time the oil comes up milky.

[ndutton]

You report two symptoms that indicate different causes:

Milky oil
Water in the oil at some point. Follow Ed's excellent advice on multiple oil changes. Further source searching may be necessary if the condition persists.

Gasoline smell in the oil
If you have a mechanical pump, a rebuild is in order.

[roadnsky]

Agree with Neil that the smell of gas in your oil indicates a 2nd issue. (Fuel pump)

Attached is an older document from Don addressing the water intrusion and some procedures...

[daveofds]

Thanks for the info. Would gas only in the oil also make the oil turn milky gray?

[Mo]

No...gas in the oil won't make it grey...that is water. I, of course, haven't looked at your engine but would like you to check something. On your water pump there is a weep hole on the bottom. Ensure that it is not plugged up with dirt.

As mentioned, you need to change the oil at least 3 or 4 times to get water from it. Even after that you will notice some condensation on the stick. The oil should look like oil though.

Here's something that can happen and it usually occurs when the weep hole is plugged on the raw water pump. There are two seals in there, if water bypasses one of the seals it goes into a space between the two and drips out...if that hole is plugged pressure can build and the water is forced past the seal and drains into the base pan. Of all the water in oil cases I've seen there were two main culprits. The seals can also wear with usage and age and need replacing or replace the pump. Trick is to ensure this is your issue.

1. Most commonly was the seals in the pump...and when it goes most people think the engine is done when it needs a new raw water pump.

2. Breach in the exhaust manifold...but that made the engine run poorly as the water affected firing of one or more pistons. (I don't think this is your issue)

There are other causes, cracked block, corrosion through a piston wall, corrosion through a water jacket....but the most common that I've seen in my 10 years or so playing with these things was a water pump seal failure. Sometimes the shaft wears on the pump as well and causes problems. Have a good look at the pump, and you could call MMI and talk to someone there to get the low down on that.

As for gas in the oil...you usually end up with pump failure and the engine won't run well and is hard to start, starving for fuel at high revs....do you have those symptoms going on?