If you can't sleep at night and think you know that much more than the hundreds of people who build and design your engine then change the darn oil and be happy. If you trust all these hundreds of people to have done their research and would like to spend the $$$ on beer (like me) then run the oil until the book says to change it. Said it b4 I'll say it again driven LOTS of miles, don't change my oil early, NEVER lost an engine. Do what u feel is right and will make you comfortable. I have my oil analyzed every second change. Cost me 11 dollars. FWIW

 

TinJim asks:<br><br>&gt; If Cummins does not ship the engine with any special <br>&gt; break-in oil then why would an oil change delay break-in of <br>&gt; the engine? <br><br>Two key points from the Cummins Tech:<br><br>1) There is no need to change the oil early to flush out Mfg Debris, as the engines are run in to the point that both the initial residue, and that from the &quot;break in&quot; during the &quot;run-in&quot; testing are both flushed. <br><br>Specifically: &quot;There is no advantage to an early oil change&quot;<br><br>2) Apparently just like the synthetic issue, &quot;new&quot; oil must have some aspect reduces wear. Think about it..... Break-in on a CTD is a case of controlled wear. The rings will not seat if the final polish is prevented by too slippery oil.<br><br>When I mentioned 3000, he indicated that would be OK (IE: No harm), except I would probably delay break-in of my engine. <br><br>&gt; Dirty oil is then better for break-in? <br><br>May be. Either they depend on the slightly increased friction as the oil is used, or the contaminants. (Which would surprise me)<br><br>Oil additives in multigrade oils are typically polymer strands that are straight when cold and curl up when warm. This allows use of a lower viscosity base (15w) for cold, yet as it warms up, the polymers artifically &quot;thicken&quot; the oil film as they curl up. Giving the effect of a multiweight by maintaining a consistent oik film thickness.<br><br>As the oil wears, the metal surfaces slowly will chop up the polymers, until they no longer have the multiweight effect. Which is why you have to replace it, even if it appears clean in a gasser.<br><br>Synthetics reduce friction so much they can use a much thinner oil film. Likewise, they don't thin out with temperature changes, so there is no need for the polymers, thus the longer service life.<br><br>My guess is that Cummins is counting on the thinner oil film of dino oil during the 5000-7500 mile period to achieve the final polish.<br><br>So despite conventional wisdom, I'm following the Cummins Tech's suggestion and not tampering with the schedule.<br><br>Have fun!<br><br>Alan