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Rudolph Diesel
Rudolph Diesel , ASE ,Master Heavy Truck Technichian
Category: Heavy Equipment
Satisfied Customers: 1942
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Rebuilt..head gasket..We had to replace cam, crank, bearings, etc

Resolved Question:

I have a c-12 cat engine that I just rebuilt because the head gasket was leaking water into the oil. We had to replace cam, crank, bearings, etc. The engine was full of slime when we took it apart. Now it is running and there is a condensation coming out of the blow by tube but the truck is not using water or oil. Oil pressure is low between 12-15 at idle and 35-40 full load. Is there something I didnt do right?
Submitted: 8 years ago.
Category: Heavy Equipment
Expert:  Rudolph Diesel replied 8 years ago.


Welcome to JA!


How many miles or hours on the engine


were the cam and bearings flaking or pitting (parts replaced)


was the spacer plate removed between the head and block?




Customer: replied 8 years ago.

The engine has 500 miles on it since rebuilt but has never been ran hard, just back and forth on test drives, it was done about 2 months ago and I am just getting the truck back on the road. The cam and bearings were pitted and flaking so we did have to mike and turn the crank and use oversize bearings. All this was done at a reputable machine shop. I am not sure if the spacer plate was removed. Originally we just did a head gasket, then ran the truck 150 miles and noted low oil psi, I decided to replace main bearings at that time and noticed the pitting so thats when we decided to take the engine down to the cam and crank. We did not dissasemble the head gasket or top of the engine again, all was done without removing head gasket a second time because we took engine out of the truck to do repairs. I took the blow by tube off of the truck today and looked inside, looks like assembly lube and slime build up a little bit inside, not bad. I put a dixie cup below the blow by port and in 2 hours it filled about 1/2 the cup with a clear liquid, looks like water. I assume if the head gasket is leaking again, it would use water and fill the oil pan with antifreeze but it is not. Some are telling me this is just condensation from assembly? Engine seems to run fine and has good power but there is condensation coming out of the dipstick tube and the fill tube when engine is running. I tasted the oil and cannot detect an antifreeze taste in the oil and oil is not milky or green.

Expert:  Rudolph Diesel replied 8 years ago.



Thanks for the information.

How many miles on the engine before the problems started?


is there anything going on with the antifreeze,,,,,,,,,, example

when you remove the radiator cap there is a buildup of stuff on the cap?


Do you do oil sample testing on this during any PM services?






Customer: replied 8 years ago.
engine has done this since rebuild was complete. there is no buildup of anitfreeze on the cap or buildup of any kind. I changed the oil once and it was a funny brown color but I assume this is from the residual junk that didnt get cleaned out of the engine from rebuild, it was completely full of slime when tore down. It was cleaned out the best we could but all was not removed. Oil is now normal color with the exception of the white assembly lube on the dipstick. Driver called this morning and said the truck had not used any water but used about 1/2 gallon of oil which I thought was normal for break-in. It has gone about 1000 miles since I changed the oil. THe truck is on the first load since the overhaul. I have not taken an oil sample yet, I will have to do that on the next PM. Last night driver called and said truck had shut down and oil psi was very low so I had him take it to KW and they changed the oil psi sending unit. I assume it was gummed up from the slime. Psi is higher now and seems to be running fine again but condensation is still noticeable as steam coming from dipstick tube and blowby tube. Ive never had a truck build up condensation in the dipstick tube, maybe I had some water in the fuel and it is burning it? It is very wierd. Truck seems to run fine but this is worrying me.
Expert:  Rudolph Diesel replied 8 years ago.

Thanks again for the update.



Sense were not using any coolant

we don't have any fuel getting pumped into the radiator,

so we know the head is ok,


if there was still some contamination in the block this would be cleared up by now.

the low oil presser will come back in time i think with the crank case making h2o and possible co in the crank case


Here is my experience with this problom


i asked about pitting in the bearing surfaces this says h20 has been in the crank case for a while

a oil sample test right now will tell you what is going on in the crankcase

we can have a problom with


the spacer plate between the head and block there is a bunch of o rings between this and the block a cracked o ring on between the spacer plate and cylinder jug will let burnt compressed gases into the crank case this will cause h20 watter in the crank case


also a cracked o ring on the top of the cylinder jug between the jug and block will do this too


and then there is pitting of a cylinder jug not enough to let antifreeze into the combustion chamber but let the compressed burnt gases into the crank case and doing what your experiencing,


if you pull the oil fill cap and hold your hand over the filler tube and it is pushing your hand away


i would pull the head and spacer plate and push out all of the cylinder packs

you can have just one of these problems or all described.


Let me know if i can help more!


Rudolph Diesel, ASE ,Master Heavy Truck Technichian
Category: Heavy Equipment
Satisfied Customers: 1942
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