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Discussion Starter #1
Ok, so I am new to the Jeep thing having just picked up a '94 4.0 with 147K. It runs strong but the engine at idle sounds like a diesel. From what I've read on here it's either a lifter issue, cracked exhaust manifold, or normal for an old Jeep. That's a story for another thread I guess....

Anyway, can someone please explain how the CCV system (the two valves located on top of the valve cover) works? Do these just pop off the valve cover or do you have to take the valve cover off to get to/clean them?

I am getting a small amount of oil in the air filter. I cleaned out the connection tube and, with the engine running, feel a very slight amount of air blowing out of the CCV valve on the front. Is this what should be happening. I'm guessing oil is getting mixed in and sent to the air filter.

Should I feel suction or blowing from the CCV valve or small tube on the back of the valve cover (closest to the firewall)? I disconnected this tube with the engine running and didn't feel anything from the valve or tube.

I am not the most mechanically inclined person but want to learn and do as much work as I can on the Jeep myself. A quick explanation of how the system works would be great. Also, I have a friend who is into old mustangs and he though we could just replace the rear CCV valve with a breather filter and plug where it currently connects to. Yes? No? I have no idea!

Thanks in advance for your help! I've posted a pic of the engine and the air filter below.



 

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Answered on the Jeep forum for you

Valve at the front of the valve cover (closest to the radiator) - part# 53030991 $4.75 each.
Valve at the rear of the valve cover (closest to the firewall) - part# 53030495 $7.75 each.
 

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Discussion Starter #3
Update...

So I solved the issue I was having with the CCV system. The port on the intake manifold was clogged up. I thought the port was part of the manifold and didn't realize until last night that it is a bolted on piece. I unbolted it and it was clogged completely shut. Ran some carb cleaner through it and used a nail to clear the clog. Once I bolted it back up and turned on the engine, I had good suction. The CCV valves/elbows at the front and rear of the valve cover seem to be fairly clean so I should be getting flow in the proper direction now and hopefully no more oil residue in the air filter.
 

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What port was bolted on....I am having similr issues. Could you post a pic of the piece that was clogged and where it bolts on!??
 

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Discussion Starter #5
Trace the line at the back of the valve cover (the one closest to the firewall) to the intake manifold. Pull the rubber elbow where it connects to the manifold. Below the rubber elbow is the bolted on inlet - it is not a solid part of the manifold. My lines and elbows at the valve cover were clean but this inlet was completely clogged shut so I had no vacuum. Unbolt the part and see if it's clogged. I needed to use a slender nail and some carb cleaner to flush it out. I will do my best to take a pic of the part tonight when I get home.
 

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Discussion Starter #7
The first picture shows the connection at the intake manifold coming from the rear CCV elbow.



The second picture shows the elbow removed. The port is bolted to the intake manifold. You can unbolt this and check to see if it is clogged. I hope this helps.

 
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