[casioqv]

There's always Mobil 1 or Delvac 1 "Turbo Diesel Truck" 5w40. My personal preference is Amsoil Series 3000 5w30, but that's so expensive and hard to find that I usually use Mobil 1 instead. I change it every 15k miles because that's the interval I've personally confirmed in a D24T via oil analysis, but the oil was nowhere near needing to be changed at that point, and could almost certainly go much longer without any increase in engine wear. Intervals on fully synthetic shorter than 15k WILL needlessly increase metallic wear and reduce engine longevity (not to mention waste money). Contrary to popular belief, the rate of metallic engine wear (judged by change in oil metal concentrations/distance determined via regular oil analysis intervals) is highest when the oil is new, and continues to fall until at least 15k miles or so, and then very gradually rises again.