30WT or 15W40?

[Anonymous Poster]

Which is better? Here in south Texas I don't use a tractor much in the winter. In my 4020 manual it says do not use a multi-viscocity oil. The multi-vis oills were not popular at that time, however I have been using 15W-40 because it is readily available.

 

[JATO_RaT]

Pat, the 15W40 has pretty much become the de facto oil of choice for almost all diesels. There are exceptions to a multi weight oil. Race cars tend to choose a 40 wt synthetic, other then that, multi weights are great. Rat...