XinnKoda

So my 2008 JKU has been consuming oil a lot lately. I ended up replacing the upper and lower intake gasket. I replaced it because it appeared to be leaking a little bit near the silicone (where the corners are). After I pulled the intake I noticed the gasket actually looked quite good and didn't have many signs showing that it was leaking internally. During this time, I used all OEM parts and even got the special silicone Jeep wants for the new gasket. I thought it would be a good idea to also replace the PCV valve since they're inexpensive and known to fail. The PCV valve was a PITA to get out but I finally got it in. The new PCV valve (also Mopar OEM) didn't seem to go in super smooth. I didn't feel the "pop" so many members have mentioned feeling. After all these repairs I've noticed that at random times, I can smell oil in the cab when I'm driving. I can only assume this is the Jeep burning oil. I pulled the tube going from the PCV to the intake and cleaned it out and then took it for a 60 mile drive. I noticed when I got home there was a pretty decent amount of oil inside the PCV tube. I cleaned it out again and am going to track it more throughout the week. I know "some" amount of oil in the PCV tube over a long time can be normal but this seems to be excessive. I'm thinking maybe the PCV valve didn't set right when I put the new one in or maybe some members on here can suggest a different PCV valve (different brand or even style?) or maybe even just a better solution. I've considered putting a catch can after the PCV valve but I would much rather fix the problem rather than just catch all the oil coming through. If any other members have any solutions at all, please let me know. It would be much appreciated! Thanks so much!

JeeP_MarK

There could be lots reasons why your getting oil in the tube. Posibilty of higher the normal crank case presume

rob_engineer

Over filling the oil can cause oil to be there and in the air filter.

XinnKoda

To give a little more info... I have been checking the oil level periodically. The oil level shows well within normal limits so I don't think excessive oil would be the cause. I also performed a compression test and all cylinders showed within normal. What would cause a higher than normal crankcase pressure? Failed rings I would think would have shown in the compression test and the engine shows no signs of head gasket. Could it be possible the new PCV valve is letting out too much vapors or may even its not seated correctly?

rob_engineer

there are lost of threads on here about 3.8 oil consumption. I think I recall some people stating that replacing the PCV greatly reduced the oil consumption. Maybe you fixed your problem by replacing it.

XinnKoda

The Jeep is still consuming oil even after the PCV was changed. I'm curious if any members can tell me which PCV valves they've used which has helped with oil consumption. The tube from the PCV to the intake plenum has oil inside of it (even after changing the PCV) so I'm thinking maybe the new PCV did not work very well.

ronjenx

The PCV valve only regulates the rate at which the crankcase is evacuated. It's a calibrated leak, variable with engine load.
If you have the correct one installed, and it rattles when you shake it, meaning it will function as designed, replacing it won't do much to mitigate oil consumption.

When the engine is running, the crankcase has a certain amount of oil mist in it, along with some combustion gasses. This mist is draw out through the PCV system. It's inevitable there will be some oil in the tube.

A compression test may not point to worn rings. You would need a leak-down test to differentiate among rings, exhaust valves, and intake valves. It can also expose bad head gaskets and cracked heads.

Smelling oil in the cab is probably a leak or oil residue burning off a hot surface on the outside of the engine.

themoneyshot

I installed a catch can because I thought I was fouling plugs. It collects about an ounce or two an oil change.