The oil pan is cast aluminum. I think that I would also try to degrease it all and lightly spray warm water around its interface area with the main engine block, then see about lowering it to try an RTV (Silicone) injection, layering RTV in on the tip of a finger, then put it all back together.
I would First verify that there is not excessive crankcase pressure in that engine by starting it, idling it, then removing the oil fill cap to check for pressure. Then, if no pressure was present, increase the engine RPM to mid-range while still checking the oil fill inlet for blow-by. If it is blow-by, the gasket on the pan may be ok and a new PCV hose and PCV valve would be needed to allow the pressure to vent normally.
I had a Volvo that did that... It had a thing called a flame trap (I think) that acted as a PCV. It was built like a cigarette lighter with the wound thin metal all coiled into a cylinder, and it crusted up with sludge at an early age. That caused a huge oil leak, which was caused by excess crankcase pressure. It pushed oil out the camshaft seal and also past the valve stem seals inside, which made smoke in the exhaust on high rpm coasts. All it was was this little PCV valve type object, which allowed the pressure to build inside when the engine speed built up. The oil just happened to find its way out the path of least resistance and restoring the normal crankcase pressure ventilation path completely cured the issue.
The V6 LS is known for melting its PCV hose and it is not possible to see it without tearing down the upper and lower air intake assembly.
By the way, I got an email from a friend and never saw it posted here... There is now a TSB for the melting PCV hoses on the V6, which goes to 80 or 100K miles (as I recall) but also extends past that in some cases... oh here is the text...
LINCOLN
The warranty on the P.C.V. hose assemblies on some LS sedans with Duratec 3-liter engines has been extended. In TSB 08N01 issued on March 9, the Ford Motor Company notes that assemblies may come loose in normal operation, so the part is now under warranty for 10 years or 100,000 miles. Also, the warranty has been extended until Sept. 30 for vehicles already past the 100,000-mile mark. Rough running and trouble starting or idling are some symptoms of this problem; a new P.C.V. hose assembly may be installed.