Anyone have a link to oil viscosity graph

[Hubert]

Anyone have a good link to an oil viscosity graph so I can compare

SAE 30 oil to

10W-30, 10W-40, and most importantly to 15W-40

5W-40 would also be nice too.

I need to put some oil in a Kubota diesel engine and its first recommendation is SAE 30 with or 10W-30 or 10W-40 as options for above 25C ambient.

[trbankii]

Something like this: https://jdparts.deere.com/partsmkt/document/english/pmac/5565_fb_Plus5015W40_0W40_files/image020.jpg

[Hubert]

Thanks,

I was kind of hoping for one like this but maybe more readable or a little clearer.

http://www.widman.biz/Seleccion/Viscosidad/Conversiones/Graph/graph.html

I looked at bob is the oil guy site then put in 100 and 11 for viscosity in the above table/graph for 40 and 100 C temps and it looks like for temps above 25C / 77F - SAE 30 and 15W-40 are pretty close equivalent in viscosity index. Then differ more and more the colder you get.

Which kind of makes me wonder why they recommend SAE 30 OR 10W-30 and 10W-40 but no mention of 15W-40 as its the most common diesel oil in the US.

[Hubert]

A Kubota rep said if it wasn't listed in manual then DON'T use it or it will void the warranty.

I went again to compare SAE 20, SAE 30, and 15W-40 and for temps above 25C-77F 15W-40 looks equivalent to SAE 30 but see where SAE 30 is more viscous at lower temps and appreciably changes. And at near freezing the viscosity difference appears significant from SAE 20 vs 15W-40. More than I would expect. As I was thinking the 15W was kinda close to SAE 20 at cold temp but 15W is still appreciably more viscous.

I kinda wonder how accurate the graphs are due to a 2 point curve fit (doesn't differentiate that I can tell for straight vs multi-viscosity) and its an unkown internet source of info and I am estimating the 2 pts from bob is the oil guy site. So if someone has a good Viscosity graph with the above oils I am still interested.