Originally Posted by Tikka
Hi
5W-30 fully synthetic all year around.
I did not realise there was a 'need' to change. Or is this only for extreme climates?
What will a 0w offer in winter that would not be suitable for summer? Presuming off course this or near viscosities are suitable for the engine.
Thanks.
From a practical standpoint, nothing. Summertime temps in N. America make the winter rating (Xw) largely irrelevant. That is to say from a 0w to a 5w and a 5w to a 10w or vice versa. The viscosities at low summertime temps in the above example is not all that significant from one grade to the next adjacent grade, especially when you consider how fast engines warm up in the summer. The viscosity difference becomes more pronounced if say you went to a 15w from a 0w and may be something to consider. Ideally you want a Xw that most closely matches what a) your owners manual states and b) expected outside temps, as these will represent what the engine builders deemed appropriate "cold" thicknesses for that engine build. (the above example does not account for engines that fuel dilute/consume oil.. that's a whole nother discussion which might call for higher viscosities than would be normally considered)
That said you can get into a whole separate ("in the weeds") discussion around (the use of) viscosity modifiers & multi vis oils. But.. keeping it simple, if you don't see temps below -35c, just use a 5w-X year round and don't lose sleep over it.