Quote:
Originally Posted by tonycarreon
hah, a minute. bob's site takes way more than a minute. makes my head spin and i feel dumber after reading.
anyway, i think the point you're trying to make is that at start up, a lower weight oil will flow better and provide more lubrication. point taken, but not in my experience. 0w are meant for cold ambient temps and i don't drive the car when it's under 50º. if the point is that it will be harder for the 50 weight to flow at operating temp than the 40, point taken and i'm aware of that. that's why this change is a "try".
if i missed the point, please feel free to make it. i can be thick (pun intended) sometimes.
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I think you sort of got the point. I do not know the specific mileage of your car so you may be right on the money... However, the point I was trying to make is that the high number in a multiweight oil effect how it flows at any temp below operating temp.
Taken from Bob's graph (numbers are not exact)
Oil type_____________Thickness at
75df
0W-20_________________40
0W-30_________________50
0W-40_________________60
A thickness of 40 is still less than ideal for startup, but it's far better than 60. I think the point that Bob was making is that there is no utility in running a heavier weight (for the high number) multigrade oil unless your engine is not reaching ideal oil pressure (10lbs per 1000rpm). If pressures are are higer than that, you're not really doing yourself any favors and could be getting less flow even with the higher pressure in some cases.
You mentioned that your experience with higher weight oils is different. Could you elaborate?