I have had the intake manifold off the 4.2 S-type replaced knock sensors, crankcase vent valve, new injector seals etc.
I ran the engine and had no codes and the intake was pulling 18 ins of vacuum.
Vacuum was sucking oil thru the crankcase vent and blowing out a lot of oil vapor thru the tail pipes. I made a restrictor to slow down the air flow this stopped the oil vapor.
Started the car this evening to do the trip cycle and something went thru the bottom of the crank case.
So I am now looking at either a new engine or rebuild this one.
In 65 years of Jaguars I have never had an issue like this one.
The rest of the car is in immaculate comdition so I am loathe to get rid of it.