Quote:
Originally Posted by 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.
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Hi, firstly, please forgive what might seem an "attack" on your statement (which it certainly isn't, it's genuine curiosity) what you wrote seems very self contradictory. Essentially it translates as fresh clean oil causes more engine wear than dirty old oil, how can that be? I am assuming this information is based upon oil analysis which determines the metallic particle content of the oil. Is there not the possability that the analysis is being "corrupted" by the fact that when you put new oil in your engine, it will very quickly pick up the residue from the old oil (which obviosly will have a fair concentration of metallic particles) and thus give an artificially high particle content reading in the early stages of the oil's life. After this initial period most if not all of the old oil (and metallic particle's) have been absorbed by the new oil and subsequent analysis would show a lower rate of particle absorbtion (which would simply be particles from normal engine wear) giving the impression that older oil causes less wear. I would be very interested to see how the analysis would read if you took an engine of say 75k miles, totally strip it and get every last drop of old oil and residue out, put it back together (using the origional metalic components) and then perform the same analysis, I would be very suprised indeed if it still indicated an initially high wear rate with new oil. With all due respect to you, in 33 years as a mechanic this is the first time I'm ever come across a statement suggesting new oil causes more engine wear than old oil.