My '79 240D is burning a quart of oil every 300 miles. The car does'nt drip too badly on the driveway, so I don't think I'm losing a lot of oil on the road. The question is: If I switch to synthetic how much will my oil consumption go down, and are the emissions from the synthetic any worse than dino ? The car runs very well, and I've been running biodiesel in it for almost 5 years now. If all of this burned motor oil is canceling out the improved emissions from biodiesel, I might be looking at a rebuild, or another car.