It was the Rotella T6 5W-40 that I had issues with [now available in 15W-40 (JASO MA/MA2), 5W-40 (JASO MA/MA2) and 0W-40 (not JASO rated!), but in the past, T6 was only available in 5W-40]. I now use T6 15W-40, and my issues disappeared. I agree, the cold viscosity difference seems trivial. I just have to go with what I experienced. It was an issue two years, two oil changes, in a row, until I switched to the 15W-40 viscosity. I love the Rotella T6 oil for my motorcycle. I bought Shell transmission oil for my tractor, based on my past experiences; used Shell Rotella in my tranctor's engine, when I changed that after I bought it, as well. Great products, great prices, IMO.
I know that more modern car engines are very intolerant of oils which are outside of their specified viscosity ranges (voids the warranty), so I suspect diesel engines are likely running with similarly tight tolerances, which won't do well with oils outside of the specified viscosity ranges. Just offering free advice, worth every penny paid for it. LOL! Cheers!
I know that more modern car engines are very intolerant of oils which are outside of their specified viscosity ranges (voids the warranty), so I suspect diesel engines are likely running with similarly tight tolerances, which won't do well with oils outside of the specified viscosity ranges. Just offering free advice, worth every penny paid for it. LOL! Cheers!