Valve Cover Question

[chuckndonna67]

I have a '88 YJ, AT, 6 banger. I have a stinking passenger cab. The rear port on the top of the valve cover emits oil fumes. I do not have that port vented to the air cleaner as standard as I was filling up the air cleaner with small amounts of oil which got soaked up by the air filter. So I just stuck a mushroom type filter of that rear port. The front port on top of the valve cover is of course the PCV valve which is working fine (plenty of suction). Now, the question: are there baffles inside the valve cover that could be plugged therefore not allowing the PCV valve to do its job in sucking fumes away from the valve housing? CAB

[Tug-n-pull]

A week ago I would have had no answer! I went to the junk yard bought a used valve cover and just wire wheeled it down and sanded it to metal and painted it for my valve seal job coming up. It has a baffle both front and rear on the one I have. My orginal is gunked up to no end. Hope this helps some what. tug

[Bounty__Hunter]

Keep the PCV. You had oil in your air filter because the PCV was working in reverse due to a lack of vacuum, either a plugged or collapsed vacuum line. Fix the vacuum lines and your PCV will work correctly, and you'll have no oil in the filter and no noxious fumes in the cab.

Check the vacuum lines going to the valve cover. One towards the front should have what looks like a plastic splice in it, connecting two pieces of vacuum tubing. Remove this plastic piece and clean the small orifice inside with a strightened paper clip or the like. This often gets clogged with carbon, blocking vacuum. Otherwise, you've likely got a collapsed vacuum line somewhere. I'd replace all vacuum hoses before I bypassed the PCV.