Do that. I always screw in a manual pressure gauge. You see them at swap meets like $5. It will tell you a lot. Typical battery powered drill will get the oil pressure up there pretty easy.
Side note. A replacement hand held grease gun line (flexible style) is also 1/8” pipe (npt) threads. It allows the gauge to move left or right some of you are standing off to the side or cannot see directly straight down. You will need a 1/8” pipe coupler to connect the gauge to the flex line. Good luck and keep us posted. Syleng1
