This was the second attempt to stop the leak. On the first attempt I replaced the gasket but the leak continued. The car needed a oil change so I decided to give the leak another try. The problem was that the pan had a bend or high spot on the back. I found this by lying a metal straight edge across the bolt holes. I "tapped" the pan into shape, used no sealant, cleaned the gasket groove and all bolt holes. I installed the gasket to workshop manual specs paying strict attention to torque and tightening pattern. The result no leaks, no smell of burned oil and no more cardboard under the car. I assumed that someone had tightened the pan incorrectly and warped it. The pan metal is pretty pliable.

 

Thanks for the heads up David!

John