I have a 70K mile L98. The PCV system is working as far as I know. With engine running I can pull the hose and PCV valve off of the driver side valve cover and put my finger over the port on the PCV valve and it has suction. Don't see any blowby and I can pull the filler cap and no oil smoke coming out. I keep having an oil leak at the back china wall and not sure if its user error while installing or if I am having other issues. The cars runs like a champ, idles smooth, no check engine light etc.

At idle, there isn't a leak but when I throttle it a little, oil seeps out from under the intake at the rear china wall. I did mess up the install the first time and think I messed it up again.

 

Sounds like you need to pull the intake and regasket the China wall again.

 

Have you verified exactly where it's leaking? An inspection mirror can help isolate exactly where its coming from. Are you positive it's not coming from the distributor seal? If the leak is small enough and you can pin point where it is you could try to "back butter" the area with something like the Right Stuff grey RTV but you have to get it very clean for that to have a chance. If you go through teardown/resealing the intake again you may want to dimple the China wall and use the the Right Stuff to seal it up, that stuff works great.

 

Could also be the oil pressure sending unit or stand off fitting for it.

 

Yes, there will be suction on that valve, it opens and closes.

With rpm, oil psi builds and blows up between distributor and block in the valley area. Then depending on intake design, it can blow out the rear chinawall.