Q: Smoking a lot and oil in the intake manifold

Thank you for your question about your 2003 Jeep Liberty. An oily, water vapor laden mist continuously flows from the engine’s PCV valve to the intake. In some engines, a significant amount of the oil vapors will condense back into liquid once that vapor hits the relatively cold surfaces of the intake. In part, that is what you are observing. It is probably pure coincidence and has nothing to do with the oil burning you have also observed.

Replacing your valve stem oil seals should resolve, or at least lessen, the amount of oil getting into the combustion chambers. Although prior to doing that, just to be sure you don’t need to tear down the engine, perform a compression test on the cylinders to make sure the rings and valves are sealing. If compression is low or uneven, that’s not a good sign.

If you do have good compression and want to replace the valve stem oil seals, YourMechanic is ready to assist. One of our mobile technicians can come to you to perform these checks and properly diagnose the smoke and oil leak firsthand for an accurate repair.