My dealer says to change oil after first 1000 miles. Is this accurate information. Along with that...I'm noticing alot of "my Brothers" are putting some miles on their outfits before using synthetic oil. Having never owned a diesel before, new or used, I have always used Mobil 1 from the first oil change. Some professional recommendation would be greatly appreciated as I am planning on using Mobil Delvac 1. Thanks to all.