Mobil Delvac is what BART (Bay area rapid transit) has changed to, they don't change there oil at all, they just change the filters and add more oil. I sell mobil in our shop and the salesman sold me on it. I have run it in my 99 F350 for about a year now, I have changed the filter once. It has been to Canada and back to california and the wife and I go a lot. I have about 16K on the oil and am thinking about changing it. I just don't want to rush into anything. Mike OB
Last edited by Mike OB : 11-23-2005 at 05:16 AM.