Why does my 89 jeep 4.0 dump oil in the air filter?

real good comp.and good hp. but i have to change air filter every week
Why does my 89 jeep 4.0 dump oil in the air filter?
Your PVC valve is leaking, stuck open or non-existant.
Why does my 89 jeep 4.0 dump oil in the air filter?
Crankcase breather plugged up,if you look on the valve cover you will see a tube that goes to the intake manifold this is the vacuum source,check to see if you have vacuum while the engine is running,just pull the tube out of the grommet and put your finger over the end of the tube do you feel any suction,if the answer is yes,then the valve cover is plugged up,if the answer is no then the vacuum passage in the intake manifold is plugged.
Sounds like the engine has a lot of miles on it. Blowby is caused by excessive wear in the pistons, rings, and cylinder walls. As the engine fires it forces exhaust gases past the rings into the crankcase. The PCV valve is a check valve that allows the exhaust gases to be pulled back into the carburerator to be reburned for emission reasons. You can check it by blowing into it. one way you can, one way you can't. Either way it's not the problem. Excess crankcase pressure(blowby)caries oil with it to the air filter where stays.
Either excessive blow-by from the engine, easy way to check that is to take the oil fill cap off while the engine is running. If it puffs smoke like a steam engine. Your 4.0 isn't long for this world. Or the PCV baffles inside the valve cover %26amp; PCV lines are clogged, causing the engine not to be able to vent properly. My 1989 Jeep had the same prblem and it ended up being the baffles %26amp; PCV lines being clogged. The PCV lines are avalible from your local Jeep dealer. Removing the valve cover and cleaning the baffles is straight foward as well.



Mercedes-Benz diagnostic technican
I may be wrong, but doesn't your pcv (positive crankcase ventilation) valve dump back into your air cleaner. Find the hose that connects to the air cleaner and follow it back to the pcv valve and try replacing it. I know it isn't very expensive. Hope that helps you
back pressure, plugged pvc,or plugged catalitic converter or muffler.
because ur supposed to change ur breather every 30k so that doesnt happen. its gonna keep doing that if it keeps doing it change ur air filter every 20k like your supposed to