I have got a real question? If these 6.7L engines are going to be requiring oil changes every 2000-3000 miles why are we concerned with using the best of oils?
I am aware of the requirement of 7500 oil changes but whe your service engine light comes on every 2k-3k what else can you do?
I have 6700 mi. on my 6.7 , and have towed a 34 ft. livingquarters horse trailer ( aprox. 15,000#). The change oil light came on just after 5000 mi. I am an amsoil dealer and will be changing it over at the next service. In both of my last trucks; 2000 ctd,qc,drw,5spd.,gear vendors o/d,banks power pac,&banks brake. & 2005 dmax, Banks 6 gun big hoss bundle,bd exhaust brake , I have used amsoil with oil changes between 10,000 - 15,000 miles, but even amsoil is not recommending extended change intervalls on the new ultra low sulfer motors.
This past oil and filter change I also went to Mobil 1 syn. but I do not plan to go way over what is recommended. Since my G30 flash my service signal has not come on. I am feeling better about that. I plan to install a bypass filter soon. My personal opinion these 6.7Ls need a bypass filter no matter what you do with it. CumminZ
This is for 2 reasons. The new emissions compliant oils saw net reduction in TBN from 12 to 10, so the oil cannot neutralize as much acid as before. This is a major part of extended drains. Next, we are going increasingly towards heavy EGR usage, which will create more acid in the crankcase then a non egr motor. These 2 factors are the main reason why Amsoil does not support extended drains on 07 up emission motors without the use of a bypass filter and oil analysis.