Originally Posted By: ccdhowell
Don't normally stir the pot, but I'm with Pablo, and Amsoil DEO, on this one. I have a modified 6.0L power stroke, live in hot Louisiana, and tow a 12k trailer often. I can tell the difference in oil. The 6.0L shears oil like mad, it may not show up on a UOA, but the engine certainly runs better on fresh oil, ie oil in 40 grade. Delo is good for about 2k miles, Rotella foams too much and generally underperforms in engine smoothness, TDT works pretty well up to 4k miles, but the DEO lasts my full 5k OCI and in 40 grade when I drain it. My money goes with DEO, you can tell the difference in engine smoothness after 4k miles.
WOW! I don't even know where to start, but here goes. I will caution that I'm going to be a bit harsh here ...
Where did you get those mileage limits? Delo only 2k, Rotella foams to much, Mobil TDT not good for much further? Only AMSOIL will save the day at 5k mile OCIs? (Just what test did you come up with to check for the Rotella foaming, by the way?)
How do you quantify engine smoothness? Are you using a seat-of-the-pants-o-meter? When was it last calibrated?
Yes - 6.0's shear 40 grades, but everything is relative. The charts posted show that T6 didn't shear that much more than did DEO. They represent a very small percentage difference. Further, shearing is over-feared. I've seen lot's of shear'd oil in UOAs and the wear metals came back fine. My neighbor has a 6.0 and we're in the midwest. I doesn't get THAT much hotter where you are. He run's dino Rotella 10w-30 in his 6.0PSD, and it runs fine. He pulls a BIG heavy boat back and forth to the lake often. I've ridden in it many times. He has also used VPB 15w-40 at times. To be honest, the ONLY differnce we can really perceive is the easier starting and less "romp" when it's really cold outside; thinner grades start up easier with the HEUI.
I fully agree that DEO is a quality made product that will peform quite well. But come now; are we supposed to believe that your undocumented, "feels like" criteria are reasonable? I SERIOUSLY doubt the distance limits you mention (ultra short OCIs) are a true matter of lube performance; rather, those are self-imposed limits with no real data to back them up.