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I checked the Amsoil site the other day. They no longer recommend Amsoil's 5W-30 Heavy Duty Diesel Oil for our CRD's. Currently, the 5W-40 European formula is the only one on the list.
After comparing specs between Mobil 1 (5W-40) and Amsoil (HDD, DEO, & Euro), and after thoroughly interrogating Amsoil tech help on separate occasions, I decided to go with Amsoil HDD 5W-30. Amsoil tech insisted throughout my calls that HDD offers the best protection possible among their oils if I don't mind risking my engine's warranty, otherwise the Euro formula is their standard recomendation (they didn't mention HDD until I brought it up and then made the warranty risk clear). I am still a bit uncertain regarding the slightly lower High-Temp, High Shear viscosity rating in comparison with the other oils listed. Amsoil was never able to give satisfactory specifics on why their HDD is better despite the lower rating, but it is very feasible given the multi-dimensional nature of engine oil wear protection. I meant to post on bobistheoilguy.com for more info but had technical difficulties. I'll probably still do that; I'm sure some of the experts there could help clear things up. With the difference being so slight, Amsoil tech support's decent but limited explanations and seemingly unnecessary insistance won me over, along with the possibility of better mileage. I'll see about posting test results down the road.