4.0 air box full of oil...help...

[WhiteKnight2]

I have the 4.0 HO and the air box is full of oil. I did some research on this problem and it seems very common. Most articles ive read show that the ccv is the problem. I also read an article that stated the tube on the bottom of the valve was too long and caused excess oil to be drawn through the tube instead of vapors. It also can be caused by excessive blowby but lets hope thats not the problem. Has anyone had this problem and been able to resolve it? I also was thinking of a catch can but thats more of a band-aid type fix and i dont want a half a$$ jeep...

Any info would help Thanks

[XJ Rat]

Check the CCV hose and make sure it is not clogged. Insure the PCV (other connection on the valve cover) is not clogged/sticking.

[bluedragon436]

had a co-worker who had the same issue... and after some research on my part.... wasn't able to find any real fix... so he replaced both the CCV and the PCV valves in complete from grommet to the end of the hose... and still had the issue.... so we ended up installing an oil catch can.. might be a "band-aid" fix... but he doesn't have an air box full of oil anymore... and I notice that his catch can doesn't fill up with oil nearly as much as the box did... so I am guessing that the huge air pull "vacuum" effect of the air being pulled from the airbox, probably caused some of the issue..

[Mudderoy]

had a co-worker who had the same issue... and after some research on my part.... wasn't able to find any real fix... so he replaced both the CCV and the PCV valves in complete from grommet to the end of the hose... and still had the issue.... so we ended up installing an oil catch can.. might be a "band-aid" fix... but he doesn't have an air box full of oil anymore... and I notice that his catch can doesn't fill up with oil nearly as much as the box did... so I am guessing that the huge air pull "vacuum" effect of the air being pulled from the airbox, probably caused some of the issue..

Isn't the other cause of this issue a engine problem? Bad rings, or something?

[default83]

i wouldnt think it would be blowby. granted it could, but you would be feeling a huge power loss

i would replace the PCV valve, as well as checking all vacuum lines to the head/intake.

[4.3LXJ]

Many times this is caused by a clogged vent (CCV) in the valve cover. As the engine gets a lot of miles on it, there is more blow by in the cylinders. There is on any motor anyway. But there are two vents IIRC and the one in the back is small and has a sharp right angle bend. If this one gets clogged, all the venting with oil vapors goes to the air box then and hence the oil.

[oderdene]

Many times this is caused by a clogged vent (CCV) in the valve cover. As the engine gets a lot of miles on it, there is more blow by in the cylinders. There is on any motor anyway. But there are two vents IIRC and the one in the back is small and has a sharp right angle bend. If this one gets clogged, all the venting with oil vapors goes to the air box then and hence the oil.

2X, check not only clogging, check hoses also. there was small rubber hose/connector on intake end, if it goes old - closes during air suction.
http://i861.photobucket.com/albums/ab180/od_999/my%20xj/IMG_4838.jpg

[brandonlp]

you can have an oil control ring go bad but more than likely it would push oil into the exhaust system, not the intake i would check for a clog in the valve cover ventilation for sure, that would be my first guess

[PolarXJ]

2X, check not only clogging, check hoses also. there was small rubber hose/connector on intake end, if it goes old - closes during air suction.
http://i861.photobucket.com/albums/ab180/od_999/my%20xj/IMG_4838.jpg

x2