The hydraulic system in my tractor that works the rams and steering uses engine oil instead of standard hydraulic fluid (which was recently changed using Delo 15-40). Problem is after moving up north, during the colder winters it is way too thick. The controls work very slowly until an hour or so after the oil warms and I'm worried about damaging seals and or the pump.
So instead of draining out 15 gallons of new oil, would it be possible to thin down the viscosity with say 5w-30? Some say it should be ok as long as the same brand and type oil is used but I'm still unsure.
Thanks,
Jon