I have rebuilt my 1984 rabbit diesel motor n/a. Everything is tight on this motor. I have been using Rotella Dino 15W-40 since first startup. I have changed the oil and filter at 20, 100, 300, 700, & 1000 miles. I know that my engine would consume oil since it is still breaking in. With the Rotella, at the 1500 mile mark, essentially 500 miles driven, I added about 1/2 quart of oil. At 2000 miles, I change the oil and filter, but this time used Mobil Delvac 1300 15W-40. At the 400 mile mark, I checked the dipstick, the oil level was right at the add line. So I added about a 1-1.5 quarts of Mobil 15W-40 to top it off. I was amazed that my engine consumed more of the Mobil than the Rotella. I have purchase a gallon of the Chevron Delo 15W-40, to start using as a top off oil, hopefully this stuff doesn't burn. My engine doesn't smoke at all at acceleration and deceleration, unlike before I rebuilt the engine! Any recommendations?