TwoXJS

Hey, guys. I just noticed today my '93 blows air out of the oil fill hole on top of the valve cover, and a lot of it! Found while it was running and I took the cap off to try and shine a light inside to look at the rockers (just out of curiosity). Got a short video with a piece of paper to sorta show how it's like. Just wondering if this is normal....I get some oil in the air box where the rear hose on the cover goes to the air box. Not sure if this is connected to it or not....

Roler

Yes , it likely is. Blocked vent tubes. When you remove them to unplug (or replace, depending the condition), you will likely snap the plastic grommets, so have a new pair at hand. Should be it.

highmileage

Pending on the miles "some" blow-by is normal. I would guess that your valve seals are worn pretty good, Another thing would be worn rings, but both of these are left up to how much you are willing to live with.

Pelican

I got oil in the air box of my '93 until I cleaned the manifold fitting that the forward CCV tube plugs into .No oil in the box and filter since.

Probe the fitting with a stiff wire or similar to make sure there is not a carbon build-up partially blocking the vacuum. Just takes a minute.

TwoXJS

@ Roler, what plastic grommets are you referring to?

@ High, she's got a little under 180K on the clock. I know in the video you can hear a knocking noise that I'm pretty sure is worn rod bearings, but could worn valve seals or rings cause that?

And finally, Pelican, I cleaned the little fitting there that the tube coming off the intake manifold goes to. Took it off, sprayed it out with brake cleaner followed by a pipe cleaner until I didn't see anymore crud. Don't know if it helped since I'm still using the same filter, but I'm going to replace it soon.

weebur

A compression dry/wet test might tell you if your rings/cylinder walls are worn.