I just got the latest issue of trailer life and someone wrote in asking if they could use the new Rotella T 5W-40 synthetic in their Cummins. It was a long involved answer but they ended by saying Cummins only wants you to use 15W-40 or 5W-30 if it's continually below 20 degrees. I just purchased the Rotella 5W-40 synthetic to use in my engine and I think that answer in Trailer Life is hogwash. Amsoil makes a 5W-40 for our engines and I understand that Cummins now offers a 5W-40 synthetic too.
Opinions from the members?
Opinions from the members?