The PCV system isn't what causes valve covers to leak - being made in the UK does!
Seriously, though: tighten the valve cover bolts (5/16" or 8mm 12-point) or pull them and replace the gaskets.
The 2 rubber hoses attached to the valve covers are the entire PCV system, and they commonly degrade, collapse, & leak, so buy some new ones. (I might have a pair...) When you pull the RHS hose (left as you look at the engine), you'll see a small plastic post inside the tube. Grab it firmly, but carefully, and pull it
STRAIGHT out of the tube. If you pull to the side even slightly, you'll probably break it (which is only a hassle - not a catastrophe). What should happen is the oil separator comes out. It's a single plastic part with a central shaft & a series of about 6 discs, each with an edge trimmed off, alternating sides. They invariably foul with oil sludge and varnish, blocking the flow of crankcase vapors. Just clean it with a rag and then with carb cleaner and reinsert it
CAREFULLY. If you break it, you'll have to remove the valve cover, then remove the splash shield from inside (8 phillips screws) and push it out. A new one is only a few dollars, but cleaning it works fine.
