WAter in crankcase

[Glenn Ellis]

Now that I cleaned the heat exchanger and reinstalled it, I began the process of purging the air in the fresh water circuit on my M25 engine. Engine under load at about 1500 rmp, temperature spiked fairly quickly, shut down and added more coolant, restarted, opening areas to bleed air and finally it would remain cool, thermostat appeared to be working properly and good water flow out the exhaust. However, when I went below to check all again there was oil being spit out the crankcase vent line on the port side of the engine. The oil level was exceedingly high and was turning slightly gray ... water. There was no indication that the engine was having a problem. I quickly shut down and drained all oil out of the crankcase.I have not had any water in the crankcase before so my thought is that air in the system may have blown a weak head gasket. Besides the head gasket, cracked head, cylinder liner or block, where else may fresh water get into the crankcase? I read Nigel Calder's procedure for flushing the engine with 2 parts Butly Cellosolve to 1 part SAE 10 oil. He did not mention correcting the leak first, but I would think it obvious prior to flushing the engine first. Am I correct?I'm going to the archives now.

 

[Ray]

Two main ways water gets into oil are...

blown head gaskets or cracks. The main areas for cracks to appear are behind or around exhaust valves, between water passage holes in the head or somewhat rarely between cyclinders.Cracks around the exhaust valves usually blows steam out the exhaust and unless severe the usually don't go into the oil. Cracks between cooling holes quite often go into the cylinders and then into the oil. Between cyclinders always goes into the oil.Blown head gaskets usually go into the oil and with diesels and their pressures a hot engine expands pressure and is a good possibility. Adding fluids to a hot engine while it is shutdown is not a good idea as it shocks many areas severly. If the engine is idling it helps mix remaining fluids and reduces shock. If the engine is very hot and then is should sit and be allowed to cool significantly before adding fluids.With the engine spitting oil out the crankcase breather you have added another dimension. A blown head gasket will put pressure into the cooling system and allow water to pass into the oil. Unless the compression rings are worn badly there wouldn't normally be enough pressure into the crankcase to blow oil out the breather. A cracked cyclinder liner or broken piston will. A broken head can sometimes pass pressure into the crankcase depending on where it is broken.I would replace the oil and filter, refill the fluids and have a qualified mechanic close by and restart the engine and try to locate the problem. Any noises the engine makes also would go a long way toward solving your problem.I can't comment on Nigels process as I am not familiar with it.Good luck my friend as you might need it.Ray

 

[Ray]

Back again with a new thought.

A severely blown head gasket could possibily blow oil out if there was enough water and pressure. Steam expands so much greater than burning diesel fuel that it could defeat the rings and pass pressure into the crankcase.Another point is that antifreeze that gets into the piston/cyclinder area will gaul pistons, rings and destroy the cyclinder walls very FAST if the engine is running so when performing any tests do it with water only in the cooling system.Ray

 

[Barry B.]

Cracked head or block

Glen,You stated that "temperature spiked fairly quickly, shut down and added more coolant". Adding cool or cold coolant to a hot engine that is not running and is low on coolant very often will crack the head or block much the same way Native Americans broke down large rocks by heating them with a large fire than pouring cold water on them. Any mechanic will tell you that you should only add coolant to an engine when it is cold or while it is running. When you add cold water to a non running engine it will quickly run down to the lower portion of the water-jacket forcing the hotter water to rise and rapidly cool those areas often causing cracks. When you add cold water to a running engine it will mix with the heated water that is flowing through the cooling system, and even though it will cool the flowing water it won’t be cool enough to crack the block. I would hope that this is not the case, let us know what you find.Barry BroylesC22 #1909 Brighteyes