I'm getting some conflicting suggestions on replacing my engine oil.
My engine is a Universal M3-20. The manual suggests SAE 30 (in warm weather) or 10W40 (in hot or cold).
I had trouble finding 10W40 so I asked a diesel mechanic who said I should be using 15W40.
I later came across some 10W40 oil but was told by a store worker that it was not for diesel engines (the oil itself says nothing about being for gas engines only)
https://www.walmart.com/ip/Castrol-GTX-10W-40-Motor-Oil-5qt/17175670
Am I getting good advice? Should I ignore the suggestion of my manual and go with 15W40? I
My engine is a Universal M3-20. The manual suggests SAE 30 (in warm weather) or 10W40 (in hot or cold).
I had trouble finding 10W40 so I asked a diesel mechanic who said I should be using 15W40.
I later came across some 10W40 oil but was told by a store worker that it was not for diesel engines (the oil itself says nothing about being for gas engines only)
https://www.walmart.com/ip/Castrol-GTX-10W-40-Motor-Oil-5qt/17175670
Am I getting good advice? Should I ignore the suggestion of my manual and go with 15W40? I