A word of warning. Look carefully at all the info on a container of "tractor oil" it frequently refers to the oil used in the older style tractors that was both the lubricant for the transmission
, differential, and as the hydraulic fluid. It is not suitable for engines. It probably would work
for awhile, but does not contain the soot holding properties and additives to deal with engine heat, etc. Any reputable diesel rated oil of the proper viscosity is usually fine in an older engine. I use Delo 400, LE, 15/40. I have had knowledgeable people tell me the old Perkins
should not have a multi weight, but I have been using it since 1983 for a lot of hours...Rebuilt one at over 20,000 hours and has another 12,000 since. Make sure its diesel rated, and change as needed. I frequently run double the hours between changes, when on a passage
. If you see oil pressure beginning to rise, change the filter immediately, even if low hours, soot could be plugging it.