I had a 740 with 110,000 on it and now have a 850 with 190,000 on it. Both cars, when the RPM hit the 4,000 mark would generate a huge, white cloud of smoke from the tail pipe and then go clear once the rpm dropped below 4,000. I doubt this is a feature. Any ideas on what would cause this?

Thanks

Michael

I know it's oil, but how is it getting in to the cylinders?