Quote:
Originally Posted by ChrisSlicks
The Winter weight is the SAE viscosity rating of the oil at 0F, while the second number is the SAE viscosity rating at 210F (i.e. full operating temperature). At a 210F operating temperature 0W-30 and 10W-30 will have the same viscosity (but different shear characteristics).
The closer your engine oil is to operating viscosity when it is started the less startup wear there will be, so theoretically the 0W oils have the advantage there, although the advantage is greatly diminished in warmer climates.
If you regularly get your engine hot (250+) then the larger concern becomes how much is the oil going to break down over time? Even some so called premium oils have been known to turn into complete garbage after 1K miles if the oil is run at high temperatures. So it is in your best interest to do your own research based on the type of driving that you do.
|
Chris, I hope you don't mind me chiming in here. I just want to make some clarifications to your post as it is a common misconception when discussing motor oil.
The first number in a multi-viscosity oil, the 5 in 5w30 for example, is a number that simply indicates how easily an engine can turn over in colder temperatures. It is not however, a viscosity. Based on what you said, a 5w30 oil would have a lower "weight" when cold, and a higher "weight" when hot. This might make sense on the surface, but to my knowledge, there is no fluid on Earth that thickens when hot, and thins when cooler.
In conclusion, a 5w30 oil will be thicker at cold temperatures than when it is at operating temperatures.
Again, not trying to be an *** here. I just wanted to clarify something
