Barry, thanks for the abstract thoughts.
My 240D's oil consumption is about a quart in 2500 miles. It may have actually gone down after almost a year on Red Line 5W-40. Before that I was using a mix of Delvac1 and Lucas Stabilizer which I don't believe in anymore (the Stabilizer that is). Also that engine noise is present even with the engine cold and the oil thick, so I don't think the oil viscosity has much to do with it if anything.
Are you saying the rod of the #1 cylinder in OM616 engines is problematic? That's the first time I'm hearing this.