Wives tale.

A PCV valve is just a one way valve. That valve is there to prevent back-flow from the manifold back into the crank case. Otherwise, you'd just have a hose and no valve. It's mostly a piece of (VERY old tech) emissions equipment. Instead of venting crank case fumes to the atmosphere, they're routed to and burned in the combustion chambers. To a lesser extent, it's also there to create negative pressure in the crank case to help the rings seal. Mostly, though, it's just for emissions.

The valve doesn't prevent anything from 'leaking'. The second negative pressure is applied to the intake manifold side, that valve is open. Period. If there's positive pressure in the intake the valve is closed. EVEN if the valve is stuck open, positive pressure in the intake prevents anything from flowing from the crank case to the intake manifold.

There are only two reasons for oil smoke where the PCV would be in the chain. Excessive blow-by past the rings or the crank case has been over filled with oil - or both.

Figure out when it smokes. At idle? Under hard acceleration? Deceleration? Off camber? Cruise? Just plain all the time? Figuring out these questions will give you an idea of where and what the problem actually is.

Common causes of oil smoke coming out the exhaust:

Valve stem seal(s)
Oil ring(s)
Compression ring(s)

Uncommon (some may not apply to Mitsus):

Blown head gasket
Cracked cylinder head
Cracked block
Blown intake gasket

If it's blowing oil smoke and it's been doing it for a while you'll be replacing O2 sensors and maybe a CAT, so put those on your list as well.

IMHO, I know this seems like a good deal, but unless you're going to do all the work yourself and you're looking for a project, it's not. I wouldn't give more than $1000 if I were planning on this being a driver. Too many red flags. There's a reason it's listed so cheap. My dad always says, 'if it sounds or looks too good to be true, then it is'.

Edward