Oil from Crankcase Breather

What did <...Cummins...> say over the phone?

Welcome to the forum.

Excessive oil coming from the breather is an indication that you have high crankcase pressure. This can be due to a number of things, some sudden and some slower to develop. Probably these are the most likely:

• Cylinder head gasket leaking
• Cylinder bore worn
• Piston rings broken or worn
• Valve stem guides worn

The fact that it is worse when loaded would make all of these a possibility.

Probably start with a compression test to see if the problem is isolated to one cylinder

Two of those seem questionable.

Leakinghead gasket and worn valve guides, if you are suggesting combusion gasses leaking into oil passages force oil out the breather, it seems unlikely. Both of those will typically result in oil consumption and blue smoke from the exhaust would be a clue.

Most of the time any such leak would run the opposite direction. Moreover, pressurizing the crankcase should not be sufficient to push much oil out with a stationary engine, breathers are typically above the recommended maximum fill level.

.

There is a way a leaking head gasket could be responsible, perhaps you did intend this as well:. If coolant is leaking into the oil, it could raise levels to sufficient heights that churning foaming and splashing fill the breather tube.

It would be a good idea to check oil level and oil quality. Specifically look for yellowish mayonaise-like paste in the oil. Monitoring oil temperatures could also provide some clues...if oil is being excessively churned, it heats up.

Don't agree. An example of a diesel engine fault finding chart can be found here

You are correct in that these faults will also result in exhaust smoke but it is more likely to be white.

A fault code chart doesn't speak to likelihood....the order in which the possible codes are listed is numerical not by frequency.

Ya know what, Ill agree with your premise on the condition it pertains to forced induction. Many diesels are turbocharged and/or supercharged, so what you wrote originally is perfectly reasonable.

The smoke referenced as blue is bluish white. It is distinctive. The code chart you provided describes it as blue/white. I say blue so as not to confuse the issue with steam/fog produced put the exhaust.

There is the remaining problem that excessive crank case pressure alone is not sufficient to cause oil to stream out the breather tube.

I agree that excessive crankcase pressure my well not be the only cause of oil coming out of the the crankcase breather, but it is certainly sufficient.

This is a breather to atmosphere - there has to be a driving force to get the oil mist from the crankcase to migrate to atmosphere excessively. For me, the most likely cause is over pressure in the crankcase, most probably caused by the phenomena that are mentioned in my original response and or from the diesel engine manufacturer's fault chart.

Not sure of the connection with super or turbocharging.

"... there has to be a driving force to get the oil mist from the crankcase to migrate to atmosphere excessively.."

This make the condition necessary, but it isn't sufficient, in and of itself. Not only is a driving force required, but additionally, enough oil must be put into the breather tube. If tye pressure isn't behind the oil it isn't going to motivate it.

The connection with super or turbocharging has to do with the pressure in the manifolds vs atmosphere. Without forced induction, pressure on the intake and exhaust manifold will typically be lower than atmospheric most of the cycle. If the valve stems and guides are not creating a good seal it will be more likely to draw air and oil into the manifolds (resulting in bluish white smoke) than pressurizing the the crankcase.

White! If it's white then water is in the bores not oil, oil burns black, I go with high crankcase pressure for all the reasons stated by others, a simple test is to block the breather tube with your finger or something big enough to cover the hole & see how the pressure builds, If it pushes the blockage aside then start with a cylinder test, & go on from there.

Bazzer

Oh my - burnt white water?

We will be dismantling the head tomorrow morning. I will update you with the findings

Problem is more pronounced only when engine is loaded may mean piston ring problems..

Problems possibly caused by some broken piston rings... Piston rings can be replaced underneath when crank case is removed, not through cylinder head..

I agree, replace rings. Leaking valve guides will produce exhaust smoke. Leaking head gasket will produce milky lube oil. Under extreme circumstances, an oil separator, sump pump system could be afixed, sending discharged oil back into oil fill tube and vapors out to atmosphere.

Some unknown internal oil sealing, metal part either broke or failed from wear.

Take it out of service, tear the engine down and rebuild it.

Do not wait to do this! Do it now!

Before or after #1⇑?

Is it possible that somebody put too much oil in this engine? You would think the oil level should not be high enough to be pushed out the breather.

Exactly.

waiting to hear

time for teardown and rebuild

Is the oil at the correct level by dipstick with the engine not running?