X15 efficiency advice

[marek4792]

How's the oil level? Did he change oil brands recently, bulk to bottled vice versa? Frigid cold can also cause a high crankcase pressure code to come up too. Make sure the vent tube and the oil drain tube to the sump isn't clogged too.
I coded at 19 inh2o a few weeks ago with little blowby, in my case had to add a gallon of oil was below the hash mark on the dipstick. Hasn't returned since..