I noticed a 1/8 to 3/16 inch wide and 3/16 to 1/4 inch long notch of metal missing from the engine block near the oil pan. That appears to be why it is leaking oil from that general area. I think the block may be cast iron so I don't want ot weld it. Would JB weld seal it? Or does anyone have a better suggestion? Also, there is a steel pipe which crosses over the bolts that hold on the oil pan. I'm pretty sure the pipe has to do with the hydraulic system. I may need to remove that pipe to remove the oil pan (grrr). If I do, I wonder how I can get air back out of the system? Is it like car brakes with some way to bleed out the air?