Strange Oil Leak - 560SEL

[jcantor]

Yesterday's beautiful weather and light traffic got the better of me so on a quick trip to northern New Jersey, I decided to push it a little and cruise at 85-90mph instead of my usual 70-75. As expected, the drive was a pleasure - these cars really are built for speed

When I got off the interstate and back down to normal stop-and-go driving, I was greated with a bit of smoke and the obvious smell of burnt oil coming out from under the hood (note - not through the tailpipe). When I got to my inlaws and opened the hood I noticed a damp spot on the top-center of the firewall, near the tranny dipstick and the PCV vent pipe on the right valve cover. The smoke appeared to be coming from oil burning off of the exhaust crossover behind the engine. Interestingly, the only areas that appeared damp with oil were on the firewall as I mentioned and on the exhaust pipe. The back and top of the engine looked dry.

My question: What about my high speed driving might have caused this and where is the leak likely to come from? Could it have been blowby at the PCV vent or possibly tranny fluid drivin up the dipstick tube??

Thanks
jlc