I was reading this Motor Oil University article --towards the bottom of the article, and if I understand it correctly, the first number (the w number) in the viscosity grade not only tells you how cold it can be and still have the engine start up, but it also controls or influences how viscous the oil is after startup. Is this actually the case? I always thought that the only thing that the first w number affected, was how cold it could be, and still be able to circulate through the engine; but that after starting the engine, the oil behaved as the second grade number.
Another way of saying this is—let's just assume 2 oils, that are alike in every way, except for the pour point depressants required to make one oil an 0w, with the other a 10w oil. So we have the two oils, an 0w-30 and a 10w-30. Once I start the car, will the 0w oil flow any quicker at cold temperatures? Or does the 30 viscosity grade kick in at that point, and both oils would flow at the same exact rate?
Going back to the article, if I'm understanding it correctly, it was saying that the oil with the lower winter grade, will also have a lower viscosity at 75 degrees F. Or have I misunderstood it?
Another way of saying this is—let's just assume 2 oils, that are alike in every way, except for the pour point depressants required to make one oil an 0w, with the other a 10w oil. So we have the two oils, an 0w-30 and a 10w-30. Once I start the car, will the 0w oil flow any quicker at cold temperatures? Or does the 30 viscosity grade kick in at that point, and both oils would flow at the same exact rate?
Going back to the article, if I'm understanding it correctly, it was saying that the oil with the lower winter grade, will also have a lower viscosity at 75 degrees F. Or have I misunderstood it?
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