Remember, the boys that blend the diesel are in the business of supplying only the minimum of lubricant to meet a spec.. (what was the spec written to cover? also note that the spec was written with the help of the producers mostly to cover diesel trucks that hardly ever stop)The producers make dollars by not providing "give-away" .. Part B, not all batches are tested for correct lube additives.. I am not saying that you should use additional additives, just providing a little food for thought. (yes I used to do engineering work for the biggest oil company on plants that make diesel ... and yes I do use a little fuel lube additive in the old diesel engine on my boat) That said, remember too that the fuel provides for the average injector pump and provides only as much lube as was in the previous diesel blends. Again, I am only providing material for thought, not condeming the oil guys nor am I lobbying for the use of additives.