89 country boy

Idk if its a common problem or if someone can tell me why i have it but i have oil in my air filter... Alot of oil! Can anyone tell me why this is and how to fix it???!?! Thanks yall

FL Denmark

the pcv vavle on the rockercover its clocked. clean it or replace .

Roler

Yep, x2. Most likely the cause.

SeriousOffroad

No Positive Crankcase Ventilation (PCV) valve on a 4.0L, just a CCV.

Oil in the air filter box is normal, excessive oil is not.

Clean out the box and drive it for a week or two and then check it again. Some folks install a catch can you catch the excess oil.

EZEARL

Shouldn't be a pcv valve from the factory but one may have installed since. If not then check the small diameter hose at the back of the valve cover to see if it's clogged. Also check where it goes into the intake manifold.

Lowrange2

This is the CCV system on a Cherokee.


(Picture says PCV but they don't know what the hell they're talking about.)

Clean this whole system out, replace the CCV valve and replace the valve cover gasket.

I'm sure it needs one anyway.

Edit: Dang, waited too long to click post. lol 5 other folks beat me.

Roler

Sorry, hadn't checked year. Thanks for correction.

offroadordnance

Be warned the valve cover grommet and the plastic CCV elbow get brittle and can break easily. I turned a five minute job into a half day affair searching down and waiting for parts after I snapped my CCV elbow. Upside was I must of had a vac leak and my high idle went to normal after replacing the grommet, elbow, and hose.

XJjustin

X2 on this, those stupid elbows break VERY easily be carefull not to tug on the hose real hard if its stuck, there not fun to replace

DFlintstone

You might want to look at "Cruisers Valve Cover Mod", in the link in my signature.

OK, here it is:

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.