Problem is you can’t find 0W-20 anywhere and if you grab it online it’s super expensive. I don’t disagree with you but I know many run other that what’s recommended in their engines. Just curious what others use.If Volvo is Speccing a 0W-20 Oil it has it's reasons, and 15W-50 is a lot thicker, Cold and Hot, than what is Specified, which means it might not flow as readily. While there are Plenty of Automotive Oils that meet the Viscosity Requirements, they might not be the best Choices in a Marine Engine, as the the Operating Conditions are far Different. But it is your engine, and you can run what ever Oil you want, even if it may not be up to what a Marine Engine needs
I just pulled my manual again and it says suitable SAE viscosity oils in temps that won’t get below 32 degrees are SAE 30, SAE 20W/50, SAE 15W/50. So I should be fine with 15W/50.Problem is you can’t find 0W-20 anywhere and if you grab it online it’s super expensive. I don’t disagree with you but I know many run other that what’s recommended in their engines. Just curious what others use.