I was going to use Mobil Delvac 1 in my PSD,but can't get it locally.I can get it online,but don't want the hassle of shipping cost, etc. I'm considering using Shell Rotella synthetic 5w40,as I can get it at most Wal-Marts. Is this oil a good choice,or should I use another brand? Thanks.

 

Any kind of synthetic or synthetic blend 5W40 should be just fine. Just make sure it has the API certification trademark on the container CH-4, CH4/SJ, CH4/SL or DHD-1 if CH4 oil is not availalble, CCG-4 is acceptable. FWIW, Ford recommends 10W30 unless towing with ambient temperature above 50 F (10 C), then they recommend 15W40

 

Any synthetic oil will probably hold up well as long as it meets the specs for diesel engines. I started using the Rotella T Synthetic just recently due to the lower cost. I believe Delvac 1 is superior, but changing the oil every 5k due to warranty issues gets costly at $20 a gallon. If extending drain intervals is the goal, then I would use the Delvac 1. I would still do oil analysis however. Until then, Rotella is a proven diesel oil and will work just fine. I'm sure some will swear by Rotella and insist it's the best. I just like the Mobil synthetics better for extended drains.

 

Thanks for the advice. I'll try the Shell Rotella synthetic.

 

Take advantage of SHELL ROTELLA 5W40 synthetic while supplies last. My inside connections at Equilon refineries say they have gotten out of the syn. oil biz. That's why Wal-mart and other retailers have dropped their $18-20/gal price tag by half.