Quote:
Originally Posted by 101Volts
I'm aware that if the oil is a Xw30 it's compatible with the engine. But, it'll cause more wear to have a 10w30 than 5w30 or 0w30 in theory - If the car engine can take it and not leak or burn oil, is there any reason to not use 0w30? I imagine it would make starts - Summer or winter - easier and get to lubricating the system quicker.
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The thing about 0W-30 is that it thickens as it gets colder just like any other oil. At running temps it's the same as any 30 oil, but of any 30 oil 0W-30 thickens less at cold temperatures. So that way for the engine, starting it up at 0° F is like starting it up at 100° F with staight 30. This is a good thing.
I don't see why any car "wouldn't take" a 0W-30 as long as it's recommended to use a 30 oil. 0W-30 still is thicker at colder temps, just not as thick, and once it warms up it's no different than any other 30 oil. I do know a few guys who swear that cold engines need thicker oil for start up protection, so they usually use straight weight oil, like straight 30. I think they should send that to Mythbusters, I personally don't think that makes any sense.
Another "concern" some people have with multi-grade oils is that multigrade oils contain viscosity modifiers which kind of take up space in the oil meaning that now you have another ingredient that supposedly might deture other ingredients from doing their job. A 0W-30 is going to have more viscosity modifiers than a 10W-30. Straight 30 has none. Personally, I really don't think that viscosity modifiers affect the oil's job of lubricating like that.
Another "disadvantage" with multi-grade oils is that they are based off of the lower grade. A 0W-30 is a 0W oil modified to not thin out as much as it heats up so that it becomes the same thickness as straight 30 at running temps. But
IF the viscosity modifiers break down then soon you have 0W-20, then 0W-10, then eventually plain 0W, whereas a 10W-30 can only break down into a 10W oil. Straight 30 will not ever break down thinner than 30. Although this is true, you have to really abuse the oil for it to break down like that. This is the reason some race car drivers prefer straight weight oils. Of course they're running 350° F oil temps!
With that kind of abuse I can see why a multi-grade oil might break down into a thinner oil.