Year-round oil viscosity

[DarkBlack]

How often is Nebraska at 104F?

 

[Obi-Wan-YJ]

How often is Nebraska at 104F?

A few times every summer. I an usually avoid tractor work when it's 100+, but there's no way you can avoid 90+, because it can hit that by noon many days in July.

 

[Obi-Wan-YJ]

I just bought a low-hour 2016 LS XR4145, their 45-horse CUT. It's overdue for an oil change.

I live in Nebraska, where we see temps between -20F and 104F every year. I use my tractor year-round, but I don't use it enough to warrant changing the oil more than once per year.

The manual says to use 5W-30 for cold temps between -25F and 68F, and 10W-30 for warm temps between 14F and 104F. If I run full synthetic oil, which viscosity would be the better choice for year-round operation?

I just downloaded another XR4145 Operators Manual, presumably for a 2020 model, that gives different oil recommendations than my 2016 manual does:

5W-40 from -22F to +104F
10W-30 from -4F to +86F
15W-40 from +5F to +104F

Both manuals list the exact same engine, so it's surprising that the temperature ranges are so different. These new numbers indicate that 5W-40 was indeed the proper choice for my climate.