Jaguar Vanden Plas 1993 XJ6

2 weeks ago I noticed small amounts of oil deposits on top of the engine and in the location where you would add your power steering fluid. 2 days later I bought some detergent to steam clean the engine. I check all fluids every 4 days. Everything looked clean. A week later I noticed the oil was back and a good amount this time. I took it in to my mechanic. He changed the O rings. I had it back for a day and massive amounts of oil was leaking. I took the car back the next morning. He then changed the head gaskets. He let the car run for 20 minutes. It kept leaking. So he ask if I can pick the car up on Monday. My mechanic is very good in my opinion. You know how these sensitive luxury cars behave. I am a woman and know quite a bit how the engine works. I studied your article on the step by step discipline on tracing where the oil can be leaking from. The Vanden Plas has a million buttons on the panel. My oil needle did not move to indicate my oil had all leaked out! Can you help me understand how t spot trouble with the car while I'm on the road? I hate breaking down.

Thanks for listening

Boss Warrior