There isn’t a hard and fast rule for setting the air regulator pressure on your pneumatic pump (regardless of the product being pumped-oil, grease, coolant, etc). Instead, set the air pressure such that your furthest dispense point is getting adequate fluid pressure and flow rate, while your closest dispense point isn’t excessively pressurized. If you have only one dispense point, set the air pressure to a level that affords a good flow rate and a decent, not excessive, pressure. High fluid pressure will cause splashing out of a crank case, blown out CV Boots, and generally speaking, a mess. While it’s a trial and error process, typical air pressure levels on an oil pump are 50-90 psi. On a grease pump it’s higher-usually 80-125 psi.