PCV Set up


C6c6s

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Aug 9, 2020
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Binghamton NY
It’s been awhile. Decided the easiest way to deal with my broken heater was to vacation the last 3 months of winter away. Time to address some issues now. I smelled oil cooking and discovered my PCV filter was popped out of the valve cover because of a rotted grommet. And wasn’t even connected to the line running to the air filter. New grommet later today, easy fix. My question is how is everyone here running their PCV set up? Stock, catch can, delete, breather filter? Pros and cons? It seems that no one sells that filter canister in the back. Just the valve for up front. I would imagine it must be pretty junked up inside. Does it really even have a purpose?
 

machoheadgames

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May 19, 2020
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Dallas, TX
Stock, no real need for anything else. On a 4.0, the front elbow needs to be free flowing and the rear elbow needs to have an orifice. If that is the case, and the hoses have no leaks, and engine is in good condition (minimal blowby), you won't have issues. No issues with mine whatsoever.

Sometimes the engines will puke oil onto the air filter, on a 4.0 this happens when the orifice elbow gets clogged. Pressure forces oil up the front elbow and down to the airbox.

On a 2.5, only one elbow is used, it's placed towards the rear, and it is hooked to the airbox. The line to the intake manifold is hooked to a threaded tube in the valve cover. When 2.5's puke oil onto the air filter, it is because the threaded tube got clogged and pressure forced oil up the rear elbow, and again, up and down into the air filter like a 4.0.
 

Flyer58

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Apr 12, 2020
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385
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Magnolia, Texas
On my 2.5L I disassembled the valve cover to clean the internal vent tubes and PCV valve and fittings. I found a small brass orifice inside the cover that was completely sealed over with tar and gunk. No way could any air get through it.

It might be worth you while to do the same to ensure it works properly.
 
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Gilaguy23

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Apr 12, 2021
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Arizona
Like what flyer says, on my 91 that uses no oil, the brass fitting in the front of the VC has a fairly small passage thru it that does get plugged or restricted after time. I use a small drill bit the same OD size and gently clear it out by hand NO drill motor. Also dosent hurt to pull the small plastic line off and make sure its clear as well. A catch can and the like is a defeating the purpose of a pcv system as it will do nothing for venting the crank case. If you have that much blow by then there is other issues like rings. The plastic 90 off the top of the VC can be had from jeep parts suppliers if yours is broken. It will also come with a new rubber gasket.
 

machoheadgames

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BTW, there is no PCV at all on a 91+ fuel injected YJ. It is a Crankcase Ventilation (CCV system) and the elbows are CCV elbows. Since you have a 2.5, clean up the tube at the front of the valve cover, change the single elbow, and you should be good to go for a long time.
 

Flyer58

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Apr 12, 2020
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Magnolia, Texas
BTW, there is no PCV at all on a 91+ fuel injected YJ. It is a Crankcase Ventilation (CCV system) and the elbows are CCV elbows. Since you have a 2.5, clean up the tube at the front of the valve cover, change the single elbow, and you should be good to go for a long time.
Ah you're right. My jeep has had long term effects of my short term memory. :)

I had all my vacuum lines off during the rebuild and remember cleaning a suction valve but t it was the power brake booster check valve.
 
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C6c6s

C6c6s

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Aug 9, 2020
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Binghamton NY
Looks like that’s the least of my problems at the moment. Rear shaft just dropped out... in traffic

FBDE0D10-583E-4DC9-BCE7-42F9EB8E9786.jpeg
 

Flyer58

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Apr 12, 2020
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Magnolia, Texas
Bummer. Hopefully it's not an expensive fix. I'm sure you noticed a lot of fluid on the ground from the transfer case. Be sure to top it off when you get it back together.
 
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C6c6s

C6c6s

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Aug 9, 2020
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Location
Binghamton NY
Me too. I didn’t see the fluid but I’m sure it’s there. Took a left into busy traffic and pop, there she went. I was able to coast across the street halfway into a parking lot. I’m just glad I didn’t get clipped by on coming traffic