Water mixing in the engine oil of Cummins 400kva Generator engine?

This topic contains 4 replies and was last updated by johnny 13 years ago
January 13th, 2009 7:08pm
Cummins engine NTA855 G4 Generator engine, water and vapour is dripping through engine breather hose and radiator coolant level going down quickly. Replace the cylinder head gasket still the problem persists. Is there any expert who can tell me the reason.
January 13th, 2009 7:09pm
If you have water in the oil, the most probable cause is a leaking liner. Head gaskets and/or a cracked head could cause this, but most of the time it is a liner.

The liners are fitted to the block and have o-rings or sealing rings at the top and bottom. These o-rings seal the top and bottom of the liner and let coolant flow around the center of the liner to cool the engine.

Many times with age, these o-rings will deteriorate or crack, causing coolant to leak past the o-rings and drain into the oil pan.

The other cause could be pitted liners, where coolant is actually leaking through the liner and into the combustion area on top of the piston. The coolant then once again drains past the rings and into the oil pan.

The other possibility is a leaking oil cooler.

Your oil temperature will often reach 220 degrees, well above the boiling point of water. When the oil reaches this temperature, the coolant that is in the oil vaporized, and comes out the blowby tube. You will often also notice condensation and "sludgy" oil/water on the bottom of the valve covers.

Your best bet in diagnosing this is to remove the oil pan and pressurize the cooling system. Inspect each liner as from the bottom and I am fairly confident you will find your problem.

The bad new is if this is the problem, you are basically looking at overhauling your engine.

Sorry for the lengthy answer, and hope it helps!
February 8th, 2009 2:43am
I don't know if it helped him, but it gave me a good t/s method, and a nother trick for me to put in the bural of useful info....lol

February 8th, 2009 10:45pm
the other guy pretty well told you how to troubleshoot for your problem just watch around your liner and piston and if it is leaking there it will tell you exactly which hole has the problem that way if time doesnt permit enough time for a complete well you can do the two holes under one head and the rods and mains and get up and running but inframe would be sugested
January 24th, 2022 7:00pm

Oil cooler faulty or crack in rocker box

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