I have a 2005 Aveo that is collecting moisture in the valve cover and beige oil sludge in the oil fill cap. Originally it was thought to be from short runs and not allowing the engine to completly warm up. It will do the same thing on a long run with a fresh oil change. It never loses coolant or oil and the coolant stays clean. Replaced the PCV valve because it seems like it's not pulling the condensation out and burning it like it should. Vacuum line to the PCV is clear also along with the one going to the air cleaner hose near the MAP sensor. Just did the timing belt, water pump, idler pully, thermostat and A/C compressor. Cannot figure out if it's an emissions problem or vacuum although it idles fine. Has anyone got any clues as what else to check. I'm about 99.9% sure it's not the head gasket because the coolant is stable. Help???