"Leaks" is too strong a word, actually. A more appropriate term might be "seepage." It's just that every time I pull the cowls off, nearly every horizontal surface at the bottom of the engine or its attached accessories has a single drip of oil dangling from it, and the rest of the compartment is covered in a fine mist of oil. This is coming from various points around the engine where just enough oil seeps out to be caught in the whirlwind of cooling air that blows around in the engine compartment.
It's very hard to track down justg where the oil is seeping, but in some cases there is enough residue near the "leak" to indicate a spot as being part of the problem. ONe such spot was the valve cover over the number 4 cylinder. That's pretty easy to fix, requiring nothing more than replacing the valve cover gasket. I took the cover off to take a look at the state of the gasket and found it to be dry, brittle, and compressed to a thickness akin to piece of rice paper.
It was extremely obvious as to why this area was leaking! I naturally assumed that if this gasket was decayed to such a degree, it was highly likely that the other three were too. I pulled off the remainder of the valve covers and found that those three were actually worse than the first I had looked at. It's clear that as previous owners had noted the tell-tale oil seepage from the covers, they had taken the expedient approach of simply tightening the screws a bit tighter. That ended up doing nothing more than squeezing any remaining cork gasket material out abd leaving a metal-to-metal contact area where the valve cover meets the cylinder head. The old cork had been compressed to hard into the cylinder head that I had to (as gently as possible) scrape it off of there. Once that was done, I installed a newer type of silicone-based (silicone: it's not just for showcase breasts anymore!) gasket. Reportedly these new gaskets never harden or wear out.
Let's hope that's true.