I used Blackstone Labs:
http://www.blackstone-labs.com/
A Fumoto valve makes taking a sample super easy and minimizes the mess:
http://fumotousa.com/
Oil analysis reports are kind of like dynos though, without a baseline they're not much help. I bought my truck brand new (4 miles), broke it in properly and sampled it religiously, adhered to the severe duty maintenance schedule, didn't tune it for over 10K miles and installed an AMSOIL oil bypass and DieselSite coolant bypass filtration system so I could keep this truck well into the Zombie Apocalypse...
Ran a mild street tune and dyno'd it once. Didn't beat on it...but didn't baby it either. Once the oil and coolant were warm it was game on. I used it for its intended purpose occasionally (towing around 8K pounds for 3K miles at 90% highway speeds for example) which gave me one the worse OA reports I've ever had.
Basically I did it by the numbers and did everything right and the motor still was in the process of self-destructing. Wasn't my first diesel rodeo either, having built my 6.0 Excursion to nearly bulletproof standards (with what was available to do so at the time) and earned a comment from a Blackstone OA report writer that said my 6.0 was one of the best wearing ones that they had ever seen, and I had obviously done it right...
The one thing good to come out of it was because I bought a leftover and the dealer doubled the factory rebate, I basically got to drive the truck for free for the 2 years I owned it. I consider myself fortunate to have discovered my developing issue before it was too late to do something about it...
What happened to me should NOT scare anyone from the 6.4. Sh!te happens, and it happened to me. I was fortunate enough to have my buddy's '08 F350 which I helped him tune, etc. and run OA's side by side with mine and couldn't believe the difference in the way our motors wore. With four times the mileage his levels were a quarter of what mine were...it was incredulous.
Fortunately I was smart enough to listen to some of the people here on the PSA who had ideas and proffered them to help me out, despite some smart azz comments I made (since I know everything). I sincerely hope that no one here ever has to experience what I did and find slivers of aluminum stuck in the oil filter and floating around their oil filter housing. That was a most sickening feeling...
I'm driving a gasser now for the time being, but would I drive a diesel again? Absolutely, likely a '98 5.9 Dodge or a 7.3 withOUT PMRs. Sure the newer engines are efficient and capable of making huge power on relatively short money, but the EPA band-aids on these motors, DPF/DOC, EGR, etc. predispose them to sludging and other longetivity compromising issues unseen on the earlier unburdened motors. I'm not the type of guy who can drive/ride anything in its stock configuration and I'm also not the type of guy who beats the crap out of something and then "returns it to stock" for warranty service/repairs. I'm not in the position to drive a $60K+ truck until the motor blows and then rebuild it the way I want it. And since I don't play PowerBall it's likely to stay that way for a while.
I spent several months making the decision to buy my truck. I was comfortable that some of the earlier 6.4 growing pains had been sorted out and surely thought the mild build approach I took was reasonable, but obviously it wasn't, at least for my truck as innumerable trucks of similar builds have enjoyed trouble-free success. Oh well, live and learn...
Your mileage may vary...and I certainly hope it does!
