I received a call for a Dover lift starting rough. What we found is the oil in the tank is dark. And the cylinder is dry. We could see an improvement when we wiped a little oil on the cylinder. But that was a temporary improvement. We loosened the head and snugged it back. We adjusted the valve for a softer start with little improvement.

I'm confident the oil viscosity is breaking down causing the packing to stick. My question is a simple one...
What weight hydraulic oil did Dover use in their units?