If I read the latest thread on this subject, the writer questions whether or not the oil-water in the separator is any more 'nasty' than the oil-water still in the engine.

 

The chemical explanation of this is that it is a distillation process whereby the vapor pressure of the water in the crankcase is added to the vapor pressure of high molecular weight fractions of oil, which enables the mixture to escape the crankcase.  Without the water present, the high molecular weight fractions would not have the ooomph to distill out.  

 

It is a trick used by organic chemists for centuries-put a steam leg into high boiling liquids, and they distill out at a much lower temperature.

 

The net result is that the distillate from an engine appears to be very gooey and nasty.  In actuality, it is still the lower boiling component of a very high boiling liquid-oil.  The oil left in the engine now has an increased percentage of higher boiling oil fractions.

 

Now the question--would I return the distillate to the crankcase? No, I wouldn't, if I had the choice.  Putting water saturated oil back into the engine is a bad scene, period.

 

Hope this chemical explanation clarifies what occurs.

 

David Jones