Whine during cylinder operation

[endless tracks]

I have. mini excavator (Volvo EC35) that had a slight whine when you initiated a command on the tracks or any cylinder. It seemed to go away once the oil warmed and I revved it up a bit. But now, warmer weather is here and it getting worse. I don't think cold oil is a problem anymore. The oil level is proper and it does not whine unless I move something. It's much louder if I move something quick. Thinking plugged filter but the oil looks pretty good. Cylinder or track speed is normal, just loud. Any ideas?

 

[oldnslo]

I believe that model has a variable volume load sense pump so pump only moves oil when a function is commanded to move.

If you feather the controls so function barely moves is the sound present and does it change when movement is faster? If yes is it a whine or growling noise?

Whine could be normal while growling would indicate a potential air leak or restriction in pump inlet / suction line.

 

[mike0000]

Any bubbles or “froth” in the hydraulic oil? I had a suction side leak on my splitter that caused a whining, ended up being the air whipped into the hydraulic oil from the leak.