Why do I have blowby coming out of my valve cover? on 1998 Jaguar XJ8

I have a 1998 Jaguar xj8 and blowby is coming out of the valve cover and going into my mass airflow sensor, going into the intake and fouling out my plugs.

Asked by for the 1998 Jaguar XJ8
1 answer
That has a 4.0L engine. It may have a broken piston ring! Have a compression test, cylinder leakage test done. On removing the spark plugs see if a plug is oil fouled, have the garage use a boreascope to examine the cylinders for scoring or damage.