It is a 1998 model, 4Y dual fuel engine running on propane. Problem started about ten months ago when I noticed engine oil looking like beige coloured milk shake. I had a post here about it and suggestions were offered here. You can find my original post in the 42-6fgu25 section, titled "Foamy Engine Oil" I finally found the cause of the condensation and it was different from the suggestions made here.

Before I get to the resolution let me give you the history. Because of the condensation I changed the oil once a month/ 15hrs engine run time. New thermostat made no difference. Coolant level did not drop at all. Compression in the cylinders were good at 187psi in each of the four cylinders, leakdown ranged between 15 to 23%. Crankcase vacuum was at 0.8 in water column, and a new PCV showed no change in vacuum. I gutted the old PCV and installed it and the vacuum went up to 9.8 in wc. This eliminated about 90% of the condensation but this was only a band aid and not a solution to the problem.

I finally rebuilt the Aisan C propane regulator and that eliminated the excess moisture in the crankcase. The extremely rich propane mixture was the source of the moisture. There was quite a bit of oil in the regulator. The condensation started after we had just gotten the propane cylinder refilled and probably excess oil in the propane took out the regulator. I will be periodically draining the regulator.

What did I learn from all this? Overly rich propane mixtures can cause moisture condensation in the crankcase.