Thanks for the reply.
I seems to me then that if I have absolutely no leaks now evidenced by an engine that remains reasonably "clean" (no significant oily buildup on the engine over time), and I change to Synthetic oil, then I probably still get no drips. That is what I thought, but from the posts here, it seemed that synthetic MADE engines leak.
I take it then that engines with oily build up may have leaks that evaporate before dripping, but if synthetics are introduced the leak rate may grow to exceed the evaporation rate, hence drips.
If this is true, might it be predictable when synthetic oil is likely to be a problem?
Just wondering if I have made an incredible intuitive leap, or gone one beer too far.