Log splitter is aerating the hydraulic oil

[mowmow]

If you can block the return (disconnect and plug both halves), and then pressurize the supply side with the 5-or-so PSI, and leave it that way for a week, you might find the leak via a small puddle forming. With that configuration, any air at the leak will eventually find its way out (assuming the leak will happen at that pressure), followed by fluid. I had a "small" leak form on the draw side of my pump (between the nipple and housing), which showed no real signs (sounds, etc) during operation, but I noticed the small puddle on the floor, as the leak was below the oil level. Pressure with plugged return would suit for higher points.

That said, most if not all of your higher points are under positive pressure during operation - no signs of leakage resulted while operating? Also, I wouldn't expect foaming to be a result of a leak on the high-pressure side of things - only on the draw side, including pump seals/body. There were (before the shaving cream ;-) ) no signs of wetness anywhere on the draw side?

 

[CJ1]

I know a guy on a tractor forum that lost their hydrostatic unit due to cavitation in the pump. From what I recall there was porosity in the filter housing allowing air to get into the oil on the suction side of the pump. Warranty covered the new unit.

I have seen lots of different things in the 30+ years of doing this. Once you get enough restriction on the inlet side of a system you cause cavitation. You don't need a leak to destroy a system. Once I start getting above 30 to 40 GPM I see it quite regularly in the oil rigs and cold temps. In dealing with big gear pumps pumping water on trucks I have it quite often. Sounds like gravel in the pump. Normally a plugged suction strainer, bad plumbing or turning the pump too fast. Sad to say but we stopped working on wood splitters as they [the customers] have given me the most headaches about not wanting to fix them. Mostly money but quite a few home made ones with poor plumbing that someone told them it was fine. Fix the problem and they still argue that it was something else! CJ