I have a 2008 Bobcat v518 telehandler that has a bit of a heating issue after prolonged use. In temperatures above 75-80f driving around with the hydro-static drive will cause the oil temps to heat up. I'm currently using fresh AW46 oil and the previous oil sample didn't show any issues. It has under 2000hrs. Should I be using AW68?
My question is- In a hydraulic system will the temps rise due to the heavy weight of an oil or too light?
ie; Light weight oil causing leakage/bypass friction from shearing, or heavy oil causing friction due to flow resistance?
I don't have to worry about cold temps, and the summer temps are in the high 80's or low 90's max. Very moderate temps here in the PNW.