I recently bought a 1991 4Runner V6 and it has a pretty good oil leak going, thats the only thing I can fine wrong with it, ive gone over it a vew times after I bought it and it appears to be in great shape for its age, except, of course for this oil leak. I assume its the main seal, but I really havent investigated it yet, I was wondering if this is a common thing?

 

Valve cover or lines in the front most likely. Seen a few of them including my old runner.