Hi palkoper.
Do you mean by saying the oil is positive that it is good or bad?

I am assuming that you mean its good, therefore you need to check the level at the oil separator.
Which should have a level in the top glass.
If you need to add oil, the recommended method is to pull a vacuum on the oil separator.
And draw the oil into the system through the oil header this will also ensure the oil header if full.
On start up check your oil differential and pressure.
Grizzly