I'll say, when you do valve cover gasket check for sludge on the driver side cover (one of the two hoses from oil separator goes back here); If so replace the oil separator (it's only $30 or clean it with brake cleaner), replace the two hoses and wrap them with pipe insulation, check and clean for more sludge on the smaller hoses where the funnel end of oil separator goes.

Try:
- to use the car for longer mileage
- to have shorter oil change like 7500mile/6mo to get rid the water/sludge that may clog the oil separator.
- or just upgrade to heated version of the hoses.

I assume you have 4.4i