For cold weather in WNY along the 2 Great Lakes, Yanmar shows 10W30 & John Deere lists 5W30 for our YM series engines.
I tried the 15W40 last winter. It was a real PAIN getting the engine going. If it had a oil pan heater, then maybe. By the end of December, I switched over to the 5W30 and it was a joy once again running the engine. I had to move so much snow.
Yanmar Self Check Tractor Maintenance doc 2/18/2014 Yanmar.com.jp for the YM series.
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John Deere Diesel Maintenance for 650/850/950/1050 with Yanmar engines
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