Oil Leak Help!

[porsche735]

I have a 1989 Carrera and am having a hard to cure oil leak on the top front of the engine. The oil is vaporizing (either high pressure or blown with lots of air). It is coming from the notorious area for oil leaks near the oil pressure switch, the oil thermostat, and the breather cover plate. I have cleaned up the entire area and pulled these 3 items out. I have installed a new O ring in the thermostat, put in a new pressure switch and washer and used some RTV on both sides of the breather paper gasket (also put a little RTV on the temp sensor inserted into the breather cover). Same problem still occurs...;-(
The problem does not happen at idle, it is only when the car is under load. Also, the two larger oil breather hoses have been replaced (and I think I put the "birdmouth" back in the right hose). I did notice that the vaccum sized line entering below the throttle body and routing to the ail tank was unplugged at one point with lots of oil in it, but that was cleaned and replaced with the resealing of the whole area.
I am stumped! The problem seems to be getting worse after each "fix". Anyone have any ideas? I think the only items not replaced is the seal for the oil pressure switch adaptor. That just dawned on me after I "fixed" the rest of the stuff and tested it to failure again... not sure if that could cause all this oil though...

Thanks,
Chris

[djdsc]

It is possible for the oil cooler to rupture and develop a leak.

You can see the failure crack, horizontal line, in the welds.