And Im doin my oil soon, the question keeps coming back into my mind...
Lets take for example..
10w30
5w30
0w30
At an operating temp of 212* F they are all an ideal 30 weight oil, all 3 are the same and there is no difference.
The difference is at start up at ambient temp, 10w30 > 5w30 > 0w30 in viscosity, with 0w30 still being too thick at ambient temp to properly flow (30 being perfect). However, I keep thinking, why do manufacurers recommend 10 and 5w30 if this is true? Why not just use the oil that's closest to being appropriate at ambient instead of ones that are even thicker than too thick?
Why do people talk about oils being "too thin" for their vehicle if they're all too thick at ambient yet perfect at operating temp?
Why do people bump up to 10w30 to stop leaks/burn off if they're all thin to the same viscosity in the end?
Also, you hear people talking about oils like 0w30 creating valve train noise because they're too thin but 5w30 or 10w30 quieted it.. But I mean, the 0w30 is already starting off thicker at start up than the 10w30 would be at ambient, so how does the noise not return as the oil thins out to operating temp?
