Quote:
Originally Posted by ZDan
The best modern synthetic multi-grades still have viscosity decreasing with temperature, which is perfectly normal. At 275F, 0w20 is going to be a LOT thinner than it is at 220F.
At 220F, 0w20 is ~7.5 cSt. At 275F, it's below 5 cSt.
Running a 40-weight oil you'll be back at close to 7.5 cSt at 275F. I've been running 5w30 in track season, may move to 5w40 this year...
If running for decent amount of time at higher temps, probably a good idea to run something thicker than 0w20... But 10w50 may be overkill!
100% agree! |
You keep throwing that graph up here but I have to ask where it's from.
Who made it?
The only other place I can find it is subaruoutback.org in a single post.
No reference to who came up with these numbers.
I also can find no other info online backing any of these numbers up.
Or for that matter, how thick any grade of oil should be above operating temps, let alone 270F.
Until then I am of the thought, run what the manual says until an oil analysis says otherwise.