Water in Oil

[Elgineddie]

Well I've been chasing this water in the oil gremlin for a bit. Mainly because it seems to come and go. I drain/flush/refill, and it stays clean for a few outings, then, like today for example, I've only run it 2x on new oil, I checked the oil before starting and it's clean, I run it for a few minutes, check the oil and find milk in the crankcase. Never a lot; maybe enough to raise the level on the dipstick 1/8 to 3/16".

So far I've performed/checked:

• Water jacket pressure test = passed; approx 1 hr @ 20psi
• Compression test (dry) = (1,2,3,4) 118, 110, 112, 124
• New AntiSiphon loop = new and mounted as high in the galley sink cabinet as possible

Other info:
Engine is, I believe, a 1977 (071377 code).
Engine always takes ~15-20 seconds of cranking to start COLD. I ALWAYS have the water turned off until after she fires and runs for 10 seconds, and I ALWAYS turn off the water and run it for 20 seconds before killing the engine. Runs great. Sounds great. No leaks anywhere on the engine or water pump.

Before I pull off the side valve cover, pull the head, or buy a new water pump, I have some questions...

• How do I know if the water pump oil seal has failed?
• I noticed the aft spark plug (#4) was wet with what looks to smell and look like water. Indication of a bad head gasket?

Thanks in advance. I promise I read the many posts on this but I can use some clarity because when it happens to you, you become myopic. Apologies.

[Mo]

OK water on a spark plug is going to form a drop, gas won't. It may also look really clean. If you can shine a light at the top of the piston see if it looks shiny, valves might look cleaner than the non affected cylinders also. Is there any steam coming out the exhaust pipe?

As for the water pump seal, an indicator, in my mind is an older pump, with no water dripping out of it. There really isn't much you can do and for some it's a last resort finding water in oil. Sometimes dirt plugs the weep hole and in that case water getting past the first seal may build enough pressure to make it past the inner seal. This would result in water in oil. The few cases I dealt with had a plugged weep hole, that said, they did require a pump rebuild following.

[Elgineddie]

Yes, I do recall some steam rising. And the rear plug #4 is definitely wet with water. Looking into the #4 hole, it's also wet and black. All other plugs are nice colored and dry.

Soooo if that's water in #4, it's a head gasket? Why would a pressure test hold if it's a bad head gasket? (Just general questions now that I think of it...)

[Al Schober]

Curious about your exhaust. Water lift? Mixing can? Some photos would be good.
Keeping those old Oberdorfer water pumps working is more of an issue as they age. I fought with mine for years, finally replaced with the new Moyer pump with ball bearing and a face seal. No more water pump issues. Yeah, they're expensive but so is my time. Time spent working on the boat is time I'm not sailing the boat.

[Elgineddie]

Here are pix front and rear of the pump... unsure the brand.

[Elgineddie]

Here is the anti-siphon loop and the exhaust setup...

[ronstory]

Dude, your scored. You have an MMI cover with the thumbwheels!

IMO, likely one of best improvements the PO could have made.

Now, the question is the origin of the rest of the raw water pump.

[Elgineddie]

Yes, I love that cover! So convenient for quick checks.

So can I assume that is an MMI pump as well? Or can it be another brand? I'm trying to compare it to pump pictures online but without a logo or part number there is always a little uncertainty.

Dude, your scored. You have an MMI cover with the thumbwheels!

IMO, likely one of best improvement the PO could of made.

Now, the question is the origin of the rest of the raw water pump.

[DDO]

The MMI pump has no grease cup on the side, and the Oberdorfer 202's have one.

[ronstory]

The nice thing about the MMI version is it has sealed bearing so no need to grease them. This is the grease cup (or lack thereof) that DDO alluded to.

The impeller is the same for both.

[JOHN COOKSON]

"NICE" WATER PUMPS

The nice thing about the MMI version is it has sealed bearing so no need to grease them. This is the grease cup (or lack thereof) that DDO alluded to.
The impeller is the same for both.

When I replaced my oferdorfer water pump, that would never stop leaking, with the MMI pump my temperature at cruise RPMs dropped 20 degrees from 150 to 130 in my RWC engine.
The Moyer pump is a much better pump.

ex TRUE GRIT

[Elgineddie]

Okay I’ll assume with this pump that the powdery buildup around the weep hole isn't enough to block it in the event the water side seal failed; so if this was a bad pump I’d know it based on water weeping. Which it doesn’t.

Of course that’s not the right way and I should pull it off BUT the wet #4 plug and steamy exhaust leads me to believe it’s the head gasket.

[Peter]

Questions

1) what type of pump is it? Does it have the grease fitting on it? Based on the photo I think it may be a MMI pump
2) water jacket pressure test - did this test include the exhaust manifold or just the block?

Your compression test suggests the head gasket is ok.

Peter

[ndutton]

Peter's post implies what I was thinking. Your symptom (water in the oil) is in direct conflict with a successful cooling system pressure test which raises questions about the test. In addition to his question about inclusion of the manifold in the test, what about the pump? Was it included?

The intermittent nature of the symptom may be in play here or in other words, I'm wondering if engine temperature might be a factor.

[Elgineddie]

Okay, I agree with you guys. The next time I’m at the boat I’ll redo all pressure tests. It’s easy enuf to isolate the pump, block, and manifold for three separate tests to hopefully pinpoint an issue.
It’s gonna be a few days but I’ll report back afterwards.

Thanks for all the help up til now!
Ed