Milky oil; process of elimination

[Hymodyne]

Did a compression check on the engine today, hoping to eliminate another potential deal breaker for this install. Compression is good on all four cylinders, ranging between 95 and 115 (the other two were 105 and 100). I was glad about this, until I noticed the milky light brown color of the oil that would jet out of the new nipple I put in (but never finished the install) for a new oil pressure gauge. When I drained the oil, which has less than one hour of running time, it was all milky brown.

I searched through many threads, and decided to proceed via a process of elimination, starting with the water pump:



The impeller shows some wear, and I will most likely replace it and keep this one as a backup. Is there a way to determine the condition of the seals? I realize that if these are the same ones that have been in place for many years, they most likely do need replacing.

James

[Mo]

James,
How was the engine running. Could you post a pick of the plugs. Plugs are a good way to figure out if the water is getting in through the top end via a head gasket leak or rusted /fractured manifold. If the engine isn't firing properly or lacking power that is a strong indication of water in the top end as well.

Just trying to prevent you from pulling apart things that may not be the problem. Need to try and zero in on the cause.

[Hymodyne]

plugs

Here is a picture of the plugs:


#3 had a slight whitish residue on it, but I haven't run the engine in nearly two months, working on other aspects of the install after it had been run and observed. all four of the plugs have dark brown to black deposits on them, due to the engine running rich, which I can live with, especially during the shakedown phase here on the hard. When the engine was running, it ran well and would idle consistently, and accel/decel with out any real issues.

BTW Mo, a gentleman who sails out of our marina is prepping his boat for a trip to Halifax, and then on the the African coast. I will try to get his particulars and forward them to you.

James

[romantic comedy]

I think is is hard, if not impossible for this pump to get water into the crankcase. It is designed with the two seals.

One seal keeps the water in the impeller chamber, and the other keeps the oil in the engine. If the water side seal goes, it will leak out the hole between the seals.

The only way I can think of to check the seals is to run the pump, and look for leaks. You could go crazy, and design a jig to pressurize the seals....

I dont know how easy your access is, but since it is off, and it has been years, you should replace the seals.

Go by a process of elimination, to find that water intrusion.

[ndutton]

I'd suggest a pressure test on the cooling system (after the pump). It's easy to do and will instantly confirm or eliminate the water jacket, head and manifold as possibilities. You can pressure test the block/head and the manifold separately if you prefer.

This test will point you in a direction.

[Mo]

BTW Mo, a gentleman who sails out of our marina is prepping his boat for a trip to Halifax, and then on the the African coast. I will try to get his particulars and forward them to you.

James

No worries, we'll look after him if he shows. We are at shearwater yacht club right in Halifax Hbr.

[Mo]

I'd suggest a pressure test on the cooling system (after the pump). It's easy to do and will instantly confirm or eliminate the water jacket, head and manifold as possibilities. You can pressure test the block/head and the manifold separately if you prefer.

This test will point you in a direction.

Agree completely Neil. I have heard of the seal going on the engine side of the pump and allowing water in the crankcase and that would pretty much be the only other causative reason for water in crankcase once the block and manifold and exhaust layout have been checked.

[romantic comedy]

Mo, how could the engine side seal of the water pump let water in the engine?

If we are talking about the same pump, I cant see it. There are 2 seals, one for water, and one for oil, with a hole in between.

[ndutton]

Mo, how could the engine side seal of the water pump let water in the engine?

If we are talking about the same pump, I cant see it. There are 2 seals, one for water, and one for oil, with a hole in between.

It's been discussed many times in the past and is universally accepted as a possible source of water incursion in the crankcase. In support of this here are a few posts from Don on the subject:

http://www.moyermarine.com/forums/showthread.php?p=31251l#post31251

http://www.moyermarine.com/forums/showthread.php?p=9587l#post9587

http://www.moyermarine.com/forums/showthread.php?p=3228#post3228

There are more, I stopped at three.

[Mo]

Here's my understanding of it.

Both my pumps are still serviceable so I haven't had to do a rebuild yet.

Both seals may be worn at the same time. Water sometimes makes it into the small area between the two seals. As the shaft turns water and the pump is making pressure some water makes it past the oil seal (engine side) and drains from the accessory into the base pan. Rebuild the pump is the cure...and perhaps a pump shaft if it had a long service life and is scored. I believe we had a few cases of that happening between last summer and this spring as well.

I have a feeling that small amounts of water incursion may happen at certain times or rpm when a seal is on the way out. May evaporate out but as the seal worsens it becomes evident on the dip stick. Really doesn't take that much water to make oil foam white and bubble on the dip stick.

[romantic comedy]

Thanks Neil, and Mo. Good to know.

[Hymodyne]

pressure test

I have read through the posts found in this thread, and the links to other threads on this subject. I going to buy new seals and a new impeller. I also plan to install a pressure gauge and schrader valve at the point where the engine connects to the pump, the brass/bronze tube that sends the coolant water into the engine. I realize I need to close off the opening to the thermostat housing. does that mean removing the dole thermostat, which has three openings (two for hoses, one for a temp sensor) and plug the opening on top of the exhaust manifold?

James

[tenders]

Did you see this post on pressure testing? With a bicycle pump and a pressure gauge, a sacrificial bike tire, and some hose clamps, you can pressure test any component of the system.

http://www.moyermarine.com/forums/showpost.php?p=66592&postcount=14

I'd suggest starting with the extreme ends of the engine to identify that there is a leak in the first place before trying to isolate any leaky goings-on in the components.

[Hymodyne]

Thanks!

Did you see this post on pressure testing? With a bicycle pump and a pressure gauge, a sacrificial bike tire, and some hose clamps, you can pressure test any component of the system.

http://www.moyermarine.com/forums/showpost.php?p=66592&postcount=14

I'd suggest starting with the extreme ends of the engine to identify that there is a leak in the first place before trying to isolate any leaky goings-on in the components.

many thanks. I will do this later this afternoon.

James

[Hymodyne]

first attempt

Got home from the university and started at this pressure test. I had recently replaced the tube on my motorcycle, so I had a donor for the valve. I used a length of fuel hose and some hose clamps for the tube that attaches to the pump:



first fill with the hose from my compressor was too much air, so the valve shot up into the air, with a geyser of water from the block following it, nearly hitting me in the head on the second attempt I was able to get the hose clamp lower around the nipple on the manifold and I tightened it as far as I could. When I added the air, s l o w l y, the top of the innertube portion of the valve began to inflate, and stayed inflated. The biggest leak of air was around the metal tube connection to the block, behind the distributor pedestal. I put a small thread-on tire pump onto the valve and got readings of around 15 psi this attempt, and then of over 50 on the second. after that, it was all down hill, as my zealous attempts to tighten the rubber around the nipple resulted in the rubber leaking.

I went to lowes and found brass fittings to cap the nipple on the top of the manifold. Tomorrow I will attach the metal valve stem (I cut it away from the innertube) to the tube instead of the manifold. even with the failures, when the parts of the pressurization system were working, the water jacket seemed to hold the air in, albeit only for about ten minutes or so, because of failures at either end.

I hope the new attempt tomorrow will work, as I believe that points to the seals on the water pump as the culprits for my milky oil. If this is the case, I will get the seals and a new impeller from Don and I will be back on the road, er, water.

James