Locating water/oil intrusion source on a Cummins 5 ton

This story continues. I have bigtime water intrusion into the oil and oil intrusion into the water on my 1972 Cummnins powered M818. See "Help needed!! 250 Cummins loose headbolt part two" posted 26 Jun 08. I pressurized the coolant system as someone suggested with the oil pan still on. Made an adapter with fittings on hand with a Shraeder valve on one end screwed into the water feed pipe on top of the head (see pics). I used o a clip on air chuck and about 10 PSI. I had drained the oil before hand and water started ti dribble out. This engine had a dead #6 cylinder identified by IR thermometer readings. So the focus has been on that cylinder. When I loosened the injector hold down clamp on #6, air started to escape. Looks like a cylinder liner problem for sure. Next step is to drop the oil pan and pressurize the coolant system again and see where the water is dripping down from. Wanted to pass on that these non top stop injectors come very easy with a crowsfoot pry bar. The one I used is from NAPA and has an adjustable angle which reallly helped. Will update after oil pan drop.

On page 2-3 fig 2-3 of the Cummins shop manual. (I think it's the same one you have) it shows a cut away head. I t looks like the bottom of the injector sleeve is exposed to the water flow thru the head. If the injector sleeve is not seated tight, when you pull the injector out you will get water, or air in this case, leaking around the injector sleeve.
There are just three O-rings sealing the cylinder liner. Mine were rotten, as you saw, but did not leak. Maybe you'll get lucky yet.

Mike, I might get lucky even if its just the O-rings on the liner. I don't think its the injector sleeve because the coolant level was full and I did not see any water coming out from the sleeve area nor was there water on top of the piston. Can see down in there there with the injector out. With water coming out of the oil pan after coolant side was pressurized I'm leaning more to the liner problem, cracked or O-rings shot. Still could be that area I guess. Should be able to isolate it more after oil pan is removed. See a reason to pull the oil cooler now to check it with these discoveries? Still may want to confirm its not the problem I guess. Don't want to do that if don't have to.

I think you're right. If it's not on the top of the piston it's probably not the sleeve. Wait till the pan is off, then if no leaks are noted check the cooler. You should be able to see a leak in the cooler with the pan off.( I think)
You going to the meeting Fri.?

Affirmative. Will be it town for a change.

If you pressurize it and coolant comes between the crank abd a main...usually #2, it is a cooler.

WillWagner, thanks. I will be looking for that and I am real curious what I will find. Won't be done real quick but will let evryone know the results.

Phil

In my experance 9 times out of 10 if you have water in the oil on a Cummins it's a cylinder liner. They are bad about getting electrolosis and eating the liners away from the outside in. You should be able to tell right away with the pan off. If one liner is leaking you might as well replace them all because the others arn't far behind.

m16ty said:

If one liner is leaking you might as well replace them all because the others arn't far behind.

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However, if you run SCA's you will stop the process as soon as you add them and as long as you keep them up, you'll be good.

Will,
Please explain SCA's

SCA, Supplimental coolant additives. Chemicals that are put into the cooling system to prevent errosion of the liners and aluminum parts. They can be added to coolant, or can be in the coolant from the manufacturer. You can add by putting bottles of it in the radiator, or via a spin on corrosion inhibitor...most people refer to this as a water filter. There are several manufacturers of the stuff, none compatable with each other, but all acomplish the same thing, Cummins DCA4, The Cat stuff...don't know what it's called or branded, Nalcool, Perry, NAPA sells some. Be aware, too much of a good thing can be bad. I do not know what happens if you over concentrate the other stuff, but the DCA will coat liners, water passages and thermostats and cause an overheat, and, the dropout causes a sand type material that gets between the water pump seal halves and causes the pump to piss out the weep hole. All wet linered engines should use some sort of SCA. It wouldn't hurt to use some on the LD, LDT, LDS engines to help prevent the corrosion that happens on the water rails and intake manifold.

Thanks Will, That helps.

Damage as a result of cavitation in very much different from erosion.

Cavitation occurs in liquid when bubbles form and implode in pump systems or around areas of a large pressure differential. In compression ignition engines, areas susceptible to damage from cavitation can form directly adjacent to the cylinder liners (wet liners) and water pump impellers. (although it is not limited to these areas). Pumps put liquid under pressure, but if the pressure of the substance drops or its temperature increases, it begins to vaporize, much the same as boiling water. Yet in such an environment, the bubbles can't escape so they implode. Following the rapid (read: instantaneous) collapse of this bubble, the resulting shock wave will remove some of the parent material from the parts of the cylinder liner, or pump impeller. Once this damage has begun, the localized defect area becomes a focal point, much like a stress riser, for further damage.

The SCA's are, in effect, liquid media treatments that coat or line the parent material. As cavitation occurs, it will remove the coating instead of the parent material. The removed coating is rapidly replaced if the levels of SCA's are sufficient.

Cavitaion will occur in all compression ignition engines due to the nature of the combustion cycle's effects on the cylinder liners.

One other place I've seen coolant getting in is the oil cooler!

I agree I've pulled plenty of bad liners myself (I think it's mostly cativation damage myself)! Just wanted to mention the cooler as I have repaired many of those also, if no leak is evident from a liner, since it hadn't been mentioned.

tmbrwolf said:

I agree I've pulled plenty of bad liners myself (I think it's mostly cativation damage myself)! Just wanted to mention the cooler as I have repaired many of those also, if no leak is evident from a liner, since it hadn't been mentioned.

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I guess I'm going by when someone wants me to look at a Cummins that's getting water in the oil they always cross there fingers and tell theirself "it's just the cooler, no big deal". Then you have to sit them down and tell them the bad news ( it's going to be more than a couple of hours fix and cost a bunch more). You remember them times more than the times it's the cooler leaking.

70deuce, Any luck on your problem?

Sorry it took awhile for an answer. I haven't had a chance to pull the oil pan yet. When I do I'll post the results and hopefully some picture evidence also. Oil cooler sounds to easy so you know its NOT going to be that.

Phil