Chris - Allow me to help out a bit. This was also posted over at diesel place, so I got some info from there.
This UOA posted above is with Devlac 1300 15w-40, for 5.9k miles (just shy of the universal average 6.6k for a Dmax).
Clearly, the numbers came right back down to "normal" with just a flush with good ol' dino oil. That leads us to only one conclusion; the Amsoil was spiking the Cu and Fe. No big suprise; at least not to me. Seen it happen too many times not to understand the relationship and reactions.
Now, the deeper question is what to do going forward? Do you go back to Amsoil? To be honest, that's not necessarily a bad decision, IF you choose to run extended OCIs and get your money's worth out of the extra cost for the oil. If you drive a lot of total miles in a year, then synthetics do make sense fiscally, by extending the OCIs. If you choose this course, then you'll know that the Cu and Fe spikes are truly not a significant wear event, but the chemical stripping of Cu, and likely at levels high enough to cause Fe wear. After a time, these will likely settle down. The underlying issue is that while this is happening, all that "noise" in the UOAs will mask any potential tell-tale signs of other problems. That's part of the risk using Amsoil during this "chemical reaction" period. And it's really hard to know just how much the Amsoil will spike the numbers; some Dmax's don't seem to react too badly, others nearly "freak out" with Cu spiking well over 500ppm, and at times nearing 1000ppm! And the Fe often will drag right along with the Cu, but at a reduced level. When this does happen, it can be quite "painful" (emotionally speaking, for a lack of a better term) because you're going to agonize over one of two choices:
1) do you choose to use Amsoil, and run out your OCIs to get the value out of the fluid? Not a bad decision, but one that has lots of risk in that you will be accumlating many, many miles before the Cu and Fe come down. It might take 50k miles for that to happen. Why? Well, you'd have to run at least 25k miles per OCI to get any "value" out of your Amsoil financially, and you'd have to probably run two OCIs at that 25k mile duration, to flush out the "chemical reaction". That's 50k miles worth of elevated numbers that can mask OTHER problems, should they arise. You'll have to "trust" that everything Amsoil tells you is "OK" is really "OK". You'll never know because of the way the Cu and Fe spikes mask other potential problems.
2) you could choose to do a few "flushes" with Amsoil, running perhaps three OCIs back to back over perhaps 3k miles each. That would hopefully be enough over 9k miles to both have the chemical reaction happen, and then flush out the resultant Cu and Fe from each new OCI. But that can be unworldly expensive to dump Amsoil 3x quickly! To put some generic easy numbers to it, Amsoil costs approximately 3x more money to purchase, and you'd be flushing 3x more often, so it would cost you 9x more money! You could run one dino OCI or three Amsoil OCIs over the same 9k miles driven. For that same 9x Amsoil cost factor, you could run about 90k miles on dino oil OCIs. The math really makes this a painful choice, doesn't it!
So you really have three choices, overall:
a) dino oils at normal intervals (this results in more frequent maintenance cycles; either a pro or con, depending upon how you look at it ...)
b) Amsoil at long intervals and put up with UOAs that are grossly skewed for many, many miles
c) Amsoil flush cycles that empty your wallet in a hurry
I can't tell you which one is right for you. I don't know your tolerance level for wasting money, doing lots of OCIs, turning away from UOAs, etc.
Once again, I feel compelled to be fair and say that I'm not suggesting or stating that Amsoil is a bad product line; nothing could be further from the truth. I've seen plenty of proof of excellent Amsoil performance in many UOAs over the years. But part of the "truth package" also includes the reality that the use of Amsoil is not without risks and choices. There are many Dmax owners that turn away from Amsoil because for them, the risks outweigh the rewards.
Only you can decide what's right for you, but at least you have good information to make your decision.
P.S. - You might read the UOA thread on the 7.3PDS by ottomatic; in there he makes a comment about using Amsoil for 100k miles in his Dmax, and he is "unimpressed" ... I have asked for details regarding that comment, and it might be directly applicable to your decision. Here is the direct quote:
"I am looking for a dino to put back in the DMAX and the toss up is between the Delo and Rotella. After 1000,000 mi on AME in Dmax I am unimpressed." (note: I think he meant 100,000 miles and not 1000,000 miles)
Dave.
