Hydraulic Fluid Moisture in 40C

[BradE]

The hydraulic fluid in my 40C was clear and clean at the beginning of January. Now at the beginning of February, the fluid is a little milky telling me there's moisture in it. I don't leave this out in the weather and I don't head out to the woods to cut if it's raining or snowing.

Before I spend $ to drain and refill the hydraulic oil tank, I was wondering:

1)Why the condensation all of a sudden? I didn't have this issue last season, although last year the temps were more consistently cold and this year we've had so many warm spells followed by freezing temps. Is this really a result of the changing temperatures?

2) I was told at the local parts store that skidder operators use a dry gas in the hydraulic fluid to clear up the moisture. Is that something I should try? Or would those types of additives raise heck with the seals, etc.?

3) If I don't take care of the moisture right now, could I get by with another three to five weeks of use and change it after spring break up, or am I asking for trouble?

4) Can I use any hydraulic fluid?

[Lavoy]

It is quite odd to build up that kind of moisture in that short of time period. I did have one once that seemed to do that. Turned out the hyd reservoir was cracked around the return line and letting water in. Heat is about the only way to get rid of moisture, and really impossible on these old girls to do that.
Seafoam is supposed to work well for moisture in hyd systems. For the cost of hyd oil, I would still drain and replace, and then put in a can of Seafoam.
Lavoy