Vacuum line / oily residue in air filter question

[Infidel Edition]

for some reason... my tablet won't let me use the search feature.

I was cleaning the air filter and noticed the top of the filter housing was guuy / oily.
its an '89 4.0.... and I remember seeing something about that being a sign that a vacuum check valve off the valve cover (I believe) or 1 of the vacuum lines associated was clogged?


does that ring a bell?
and does anyone know which valve or line is clogged ~ associated with the oily film?

[Infidel Edition]

I'm thinking the crankcase venalation hose... but not sure.
also is it the entire hose? or is the PVC valve a separate piece...

[prerunner1982]

I have read it is the PCV/CCV valve on top of the valve cover. Front one....I believe.
I have a similar issue and have tried to clean out all the hoses and valve and still happens. The grommet on my valve was worn and it would not seat correctly to the valve cover so I made a gasket for it.

I am thinking about putting a small cone shaped filter on it instead of it going into the air filter. That way it is still filtered but it can leak if it needs to. lol.

[Infidel Edition]

I read something (just googling...) about a filter on the inside of the valve cover that needs to be replaced?

but I also read a thread that the pcv valve should be changed out on a regular service interval... is that the entire hose?

I'm still a day out from driving home. I was hoping it was just swapping a valve from the gromitpiece on the top of the cover... anyone know?

if I have to pull the cover, I'll do it next weekend

[prerunner1982]

the "PCV" valve is just the part on top of the valve cover.

[4.3LXJ]

Try this:

Cruiser’s Valve Cover Mod

Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.


Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets

[ParadiseXJ]

I've done this...it works.

A couple of other things...

1.) There is NO PCV valve on your Jeep...only a CCV. (a 2.6mm metered orifice on the back of the valve cover) attached to the hose, attached to the intake manifold.

2.) Remove the small hose, carefully, so's not to lose the little white tip, the metered orifice, and clean out the hose and orifice with carb cleaner and/or compressed air to make sure it's clear of oil/goop.

3.) Make sure your grommets on the valve cover are in good shape and not cracked.

4.) Make sure the rear grommet is clean and in good shape. I took a look at mine...it looked fine...on the outside. Other than the little bit of rubber sticking out, this is what it looked like:

http://i168.photobucket.com/albums/u196/chasdwitt/ALL%20JEEP/076.jpg (http://s168.photobucket.com/user/chasdwitt/media/ALL%20JEEP/076.jpg.html)

But, when I flipped it over it looked like this, swollen and puckered like a...well a picture tells a thousand words. I could not get much air through that even blowing on it with an air gun, let alone the passive air from the valve cover.

http://i168.photobucket.com/albums/u196/chasdwitt/ALL%20JEEP/075.jpg (http://s168.photobucket.com/user/chasdwitt/media/ALL%20JEEP/075.jpg.html)

...AND this is what it's supposed to look like (new):

http://i168.photobucket.com/albums/u196/chasdwitt/ALL%20JEEP/077.jpg (http://s168.photobucket.com/user/chasdwitt/media/ALL%20JEEP/077.jpg.html)

I now have ZERO blowby on my air filter after running it for a few thousand miles. Good luck.

[Infidel Edition]

Try this:

Cruiser’s Valve Cover Mod

Most early and even later Renix 4.0s could be bothered by excessive oil in the air cleaner box. A fix from my old days as Service Manager at a Jeep dealership follows. Information was provided to me from a buddy at JeepTech during those days. I don’t believe it ever came out in a Technical Service Bulletin.


Remove the valve cover and turn it over. Next, remove the fluted tubes that are now facing you by removing three screws on each. Chop 1 inch off each of them. Then, about a half inch up from the area where you just sawed them off, drill a half inch hole in the tubes so the holes will face the rear of the valve cover. Clean and de-burr/sand all rough edges nicely, clean with solvent, and reinstall. Don’t be concerned about the chintzy gaskets that will probably crumble into oblivion when you remove the fluted tubes. They can go back together without gaskets


I've done this...it works.

A couple of other things...

1.) There is NO PCV valve on your Jeep...only a CCV. (a 2.6mm metered orifice on the back of the valve cover) attached to the hose, attached to the intake manifold.

2.) Remove the small hose, carefully, so's not to lose the little white tip, the metered orifice, and clean out the hose and orifice with carb cleaner and/or compressed air to make sure it's clear of oil/goop.

3.) Make sure your grommets on the valve cover are in good shape and not cracked.

4.) Make sure the rear grommet is clean and in good shape. I took a look at mine...it looked fine...on the outside. Other than the little bit of rubber sticking out, this is what it looked like:

http://i168.photobucket.com/albums/u196/chasdwitt/ALL%20JEEP/076.jpg (http://s168.photobucket.com/user/chasdwitt/media/ALL%20JEEP/076.jpg.html)

But, when I flipped it over it looked like this, swollen and puckered like a...well a picture tells a thousand words. I could not get much air through that even blowing on it with an air gun, let alone the passive air from the valve cover.

http://i168.photobucket.com/albums/u196/chasdwitt/ALL%20JEEP/075.jpg (http://s168.photobucket.com/user/chasdwitt/media/ALL%20JEEP/075.jpg.html)

...AND this is what it's supposed to look like (new):

http://i168.photobucket.com/albums/u196/chasdwitt/ALL%20JEEP/077.jpg (http://s168.photobucket.com/user/chasdwitt/media/ALL%20JEEP/077.jpg.html)

I now have ZERO blowby on my air filter after running it for a few thousand miles. Good luck.

I've gotta pull the head off in the near future... it's 'weeping' out the side = so it's within ##### miles of crapping out.
so I'll hit both above + other things I've been putting off.

[Infidel Edition]

picked up a new grommet and hose
...a set of new valve cover bolts (old 1 broke... time to replace all)

and noticed the sweating out the side of the head was a little more than usual. So I picked up a new cylinder gasket, intake/exhaust gasket, and water inlet gasket...
couldn't find bolts at the local parts stores ~ wound up ordering a set online for $30.

gonna take over my dads garage and pull the head and do a little maintenance.
:smiley-chores003: