Re: Any long-term Rotella T6 users....thoughts..?
I use standard Rotella 15w-40 in all of my diesel engines, with the exception of our common rail TDI.
I have used Rotella for at least 12 years, and no problems yet. Its funny though, back in diesel school I had an instructor that said he only used Delo because Rotella left a film on everything. I always thought to myself, "isn't that the point of oil??" Anyhow, I like it a lot.
The TDI uses Castrol 5w-40 that is spec'd for VW. It still under warranty, so I figured its best to use what they want, especially should something catastrophic happen. I would think they would be sampling oil in that scenario. The previous TDI (two 2001 ALH's) both had T6 in them. Worked great, but that's the weight of oil they were designed to run on. One of them I sold to a friend with 210,000 on it (now almost 350,000) and still going strong. I don't think I would be running it in an engine that calls for 15w-40, however.
With all of that said (and Im not going to mention the name of the dealer here), when I worked for a Kubota dealer way back when, the owner refused to order in any compression rated oil. All of his new Kubotas were filled with 10w-30..... (I quickly left that job), but I still didn't see any failures that I could even remotely blame on the oil. Would I ever do that, no! But, like I say I have seen it done and in the little over a year I was there I never saw any of them come back for engine problems.
2007 John Deere X748
1991 John Deere 332
1973 John Deere 140 H3
1973 John Deere 110
1974 Case 646
1961 Cub Cadet Original
1979 Sears LT10 36 (restored, it was my first tractor)