Need CCV help - oil in filter (YJ)

[Atlwheeler32]

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.

 

[JPNinPA]

From what I understand the air is circulated in the valve train. The filter side is the inlet and the intake side is vac outlet. If the hose is clogged you will get oil on the filter. The CCV should pop out of the valve cover, but be careful as they break easy. Replaceable but difficult to pop out and in. If oil leaks around the base you could add an o-ring to it.

Paper filters are good. WIX or Purolator are good. Also consider changing the oil filter. Some do not have a sufficient valve to keep the oil in the upper part of the engine. This leads to valve train noise.

 

[Bounty__Hunter]

There are no CCV 'valves', the plastic pieces in the valve cover are simply elbows, they do nothing but change the direction of the air flow.

You are correct in that it's a CCV system, or Closed Crankcase Ventilation. The air you feel blowing out the tube at the front of the valve cover means your CCV system is running in reverse, forcing crankcase pressure and oil into the airbox. This is generally caused by a clogged CCV tube, usually at the restriction orifice. This orifice is somewhere in the two tubes and the carbon buildup is easily removed.

Pull the rear line at the valve cover and make sure it has good vacuum into the intake manifold. This vacuum should pull crankcase vapors into the intake manifold to be burnt in the engine. This vacuum also causes clean air to be pulled into the valve cover from the front tube.

 

[Atlwheeler32]

Also consider changing the oil filter. Some do not have a sufficient valve to keep the oil in the upper part of the engine. This leads to valve train noise.

I did not hear the valve train noise until after I changed the oil. I was in a rush and was forced to use a Fram filter from W-mart. I have heard that this could lead to the noise issue. Any recommendations on oil weight and filter brand?

 

[Atlwheeler32]

Pull the rear line at the valve cover and make sure it has good vacuum into the intake manifold. This vacuum should pull crankcase vapors into the intake manifold to be burnt in the engine. This vacuum also causes clean air to be pulled into the valve cover from the front tube.

Bounty

What does it mean if I do not have suction from the rear line (suction from the intake manifold)?

 

[JPNinPA]

In your first pic above the rear CCV valve at the top of the pic has a vac hose connected that goes to a tee and then into the intake. Be sure there es a good connection as that is how the pressure in the valve train gets regulated. By drawing air out into the intake fresh filtered ain't comes in through your filter. If that rear hose is clogged or not connected any pressure from the valve train gets pushed back to the filter. This is how oil gets on the filter.
You may want to pull both lines off, check and clean them. Then be sure they have a good seal when replaced.
The other side of that tee goes to a vac resivior under the battery and to your HVAC system if there is a leak in that section you will have the heater only work out of the defrost vents. If this is the case be sure to fix that as well.

In all if there are vac leaks you will have a rough and high idle.

 

[Atlwheeler32]

In your first pic above the rear CCV valve at the top of the pic has a vac hose connected that goes to a tee and then into the intake. Be sure there es a good connection as that is how the pressure in the valve train gets regulated. By drawing air out into the intake fresh filtered ain't comes in through your filter. If that rear hose is clogged or not connected any pressure from the valve train gets pushed back to the filter. This is how oil gets on the filter.
You may want to pull both lines off, check and clean them. Then be sure they have a good seal when replaced.
The other side of that tee goes to a vac resivior under the battery and to your HVAC system if there is a leak in that section you will have the heater only work out of the defrost vents. If this is the case be sure to fix that as well.

In all if there are vac leaks you will have a rough and high idle.

JPNinPA - thanks for your response.

I pulled the line at the back and can blow through it so there is no clog. I was going to replace the CCV valve thinking the issue might be there. Before doing that, I pulled the rubber connection at the intake manifold and placed my thumb over the opening. There is very little to no suction. As noted in my first post, I am getting some oil in the air filter and there is a very slight blow coming out of the front CCV valve. I am going to check for leaks tonight but the Jeep idles fine and at about 500-600 rpms. Any other thoughts?

 

[JPNinPA]

With the engine running there should be some vac at the intake. If you have leaky rings you may be burning oil and have significant blowby that is more pressure in the valve train. But the blowing would feel like another exhaust.

Just ran out and checked mine. With all in place and engine idling, I removed the oil cap and felt for pressure. None. Replaced the 710 cap and pulled the CCV line from the intake, engine revved. I quickly placed my finger over it and there was good suction from the intake. The idle lowered lower than normal. I don't have a vac meter to tell how much but it held really good.

 

[Bounty__Hunter]

I was going to replace the CCV valve

There are no 'CCV valves', only plastic elbows. Pull the rear hose at the intake manifold and check for vacuum there. If little to none you may have a vacuum leak elsewhere.

 

[Atlwheeler32]

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 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.

 

[Bounty__Hunter]

Good to hear.

 

[JohnnyO]

I did not hear the valve train noise until after I changed the oil. I was in a rush and was forced to use a Fram filter from W-mart. I have heard that this could lead to the noise issue. Any recommendations on oil weight and filter brand?

These days Fram construction is cheap and the anti-drainback valves leak, this causes the rattle. I use Purolator PureONE filters (the textured can is sweet) about $5 from K-Mart. Wix, NAPA Gold, and even Wally-Mart SuperTech are all perfectly fine filters and better than Fram. I use Valvoline Max Life 10w-30, change every 3000 miles, and don't have any problems. I occasionally send the used oil to a lab just for kicks and the Used Oil Analysis (UOA) is fine.

Newer SM and SN rated oils have less zinc so as not to contaminate the cats on oil burning engines but this is not good for older engines that have flat tappets and not roller lifters. High mileage and diesel-rated oils have more zinc. I have used diesel-spec Rotella 10w-30 syn blend in the Jeep but oil consumption went up so I went back to Max Life.