First of all, this is a dead horse. ... and I'm just as guilty as anyone else for contributing to this.
Some background here. Ponch and I have Dmax trucks, so his concern and quest are primarily based upon the Dmax/Amoil UOAs he and I see here, and over at dieselplace.com. To that end, Ponch is right; there is an elevated propensity to see some premium synthetics (certainly not limited to Amsoil) cause elevated metal counts. Some of the UOAs can see REALLY high numbers, such as 300ppm, 500ppm, 600ppm, and I've even seen one with 900+ppm!
No- it does not happen to all engines.
No- I've never seen or heard of this issue manifesting into engine destruction.
No- there is no irrefutable proof that this is desirable or detrimental.
Here is a recent thread where I list many UOAs where high Cu and Fe are present along with premium synthetics. (look about 1/2 way down).
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2389591&page=2
The overall quantity of approximately two-thirds of the UOAs have high Cu and/or Fe. This is not an isolated incident folks; that's a preponderence of evidence. And that only accounts for two years I went back here on BITOG. If you visit other sites (Duramax sites in particular) you'll see it's REALLY prevelant with that engine series and Amsoil. I will note that because Amsoil has a higher sales volume than does RL or RP, they are (by sheer numbers) going to have more UOAs with high Cu/Fe. I am noting the difference between quantity and percentages here.
Here is a recent thread with 11 pages of posts on this very topic:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1879756&page=1
There is plenty to read there, and make one's own conclusions. I would only ask that you read all of it, or none of it, because taking any part of it out of context does no serivce to either point of view.
Also, as far as the "leaching Cu from the cooler" topic see that same thread:
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1879756&page=10
In there I talk about the cooler in the Dmax. It is NOT, NOT, NOT, NOT, NOT a copper tube type cooler. There is a small amount of Cu in a Dmax cooler, because it's a stacked plate heat exchanger and not tube-n-fin. Check out page 10, bottom two posts. I explain why the Cu leaching is grossly over-exaggeraged because the Dmax does not have hard Cu lines in the oil cooler system. The typical Amsoil answer of "cooler leaching" only makes sense to those who do not understand what kind of cooler the Dmax has; if you do understand it's materials and construction, you realize that is a convenient answer that is baseless in reality.
I would agree and embrace the following statement:
Using Amsoil (that is the brand of the thread title, so I'm zeroing into that) where high Cu is present has not resulted in any engine failures that I'm aware of from any source of information. I believe Amsoil to be a reputable copmany, and I've personally recommended and installed Amsoil in friend's equipment and never flinched or winced; they are good products.
That being said, Amsoil is not a one-size-fits-everything product, either. There are some applications where it may not make sense to use it. The Dmax/Amsoil situations come to mind, and are the topic.
One common comment heard about using Amsoil is that the high Cu will eventually normalize over time. I generally agree with that; I've seen it happen. However, depending upon magnitude of the "high" Cu, that might take three, four or more OCIs. If one has 684ppm of Cu (a recent Dmax/Amsoil UOA I've noted) it would probably take at least four OCIs to bring the Cu down to a reasonable level.
So you have two choices:
1) do several flushes with Amsoil at 3k mile intervals (VERY EXPENSIVE, as you could use one dino run for that same duration)
2) use Amsoil out to 25k miles per OCI (per their recommendation and/or warranty limit at 3x OEM OCI), and your four OCIs could equate to 100k miles until you see "normal" Cu. You risk 100k miles of masked Cu counts, and that can hide other damage (as noted by 30,000 UOAs by J. Fitch, as quoted in one of the above links).
http://www.machinerylubrication.com/Read/646/copper-diesel-engine-oil
Frankly, for me, neither one makes much sense, in that application.
