Newbie on this forum, sorry if this has been covered before.
I don't mean to be unduly argumentative, BUT, I just found the source of an odd oil leak on my AU-II with 230,000km (I've had it since buying it as a demonstrator in 2000). The leak seemed to be from the timing cover, but once I got the PS pump and mounting bracket off, that area all looked pretty clean.
My leak was associated with the lowest mounting bolt for the PS Pump mounting bracket. That bolt is smaller than the other two - a 10mm head and about 4" long. The hole in the bracket and the block are the same size as for the other (larger) mounting bolts, so there is lots of space for oil to leak out.
You can see the amount of oil that's come out onto the white tissue underneath the bolt, and some of the spray on the engine itself.
I don't know if there was originally a seal or a sleeve installed in the block, but if there was it's not there now. I loaded some (6) O-rings onto the bolt (which has a step-down in the shaft diameter about 12mm from the head).
I got these O-rings from a champion assortment (blister pack) available from your favourite auto store. Bought two sets and loaded two sets of O-rings in the following sizes and order - first on was the 3/16", then the 7/32" and finally the 1/4".
You can see that the rings protrude beyond the mounting bracket and will extend into the engine when the whole lot is assembled again.
It all seems to seal now, and no evidence of leaks so far.
I did wonder if this is leaking because the crankcase pressure is higher than normal, perhaps a broken PC valve?