I am going to change the oil in a new to me John deere 310c. Should i use rotella t4 15-40 or the semi synthetic t5 15-40 or t6 5-40 (or other full syntetic grade In nortwest ontario canada and will be used in winter -25Celcius Thanks
Welcome to HEF gumbellion !
I'd go t6 5w-40 for easier starts a longer drain intervals.
If you have a good block heater and plug it in or park it inside a warm building you don't need to spend more for synthetic oil.
How many hours a year do you expect to use it? I use my machine approximately 200 hrs or so a year and figure why waste the money on synthetic when I’m going to change it AT LEAST once per year regardless of 1 hour used or 200.
If it's the typical homeowner machine, and you won't plug it in to start in the winter, then I'd run 5w30. If you plug it in, and or do full days work in peak of summer heat, maybe 15w40. Synthetic is not worth it unless you're benefiting from extended drain intervals, and benefit from better heat tolerance.
So i went to Canadian Tire and the synthetic T6 5w40 was on clearance for only $20 a pail more than the T4 15-40. It seemed like a no brainer to get 2 pails of it which should last several years. I a couple leaking hoses from the loader this morning and dropped them off to get new ones made up. This weekend I plan to change oil, filter, hydraulic filter, fuel filter and I hope to have this this thing in tip top shape on to time!