Are you supposed to service these through the yellow line on the AC manifold set?
The oil going thru the gage is not a problem?Yes...same as adding freon.
Yes, he talks about it at the 8 min mark. ThanksApparently not as this is how it's done. Here is a great How-To video by Chris Fix on how to service your a/c system. Adding oil is mentioned further into the video.