Time to open up the tank. I had a hell of a job opening up the well-sealed access cover. See Picture 1. With the cover off, and cleaned up with MEK I applied more goop to the rear of the sight glass, and while I was at it, sealed the outer edges of the tank even though there was no indication of leaks from there. We will have to wait and see whether this all works.
My frustration is that I cannot get at leaks coming from inside the cover plate behind the transparent inspection window. If this is the source of the leaks, the top cover will have to come off, and the sight glass and its backing plate will have to be removed and cleaned up. In fact, I will probably have to purchase another sight glass. I can see why others have given up, permanently sealed up the sight glass holes with a blanking plate, and purchased a gauge that sits on top of the tank.
