Originally Posted by OilUzer
Originally Posted by 03s
Regarding viscosity chart:
5W30 low temp range (arrow) stops @ -22°F ... Below that 0W30 is recommended.
both oils high temp range (arrow) stops @ 104°F ...
Then what should be used above 104F? 0W40?
if xW30 was desired, they should have continued the xW30 lines past 104F for consistency (like they did for 0W30 cold temp) ... or they need to specify a higher grade for over 104F.
Maybe they don't want you to operate at above 104F.
For starters the chart is just a guideline, it's not like a 5w30 is all of a sudden gonna stop lubricating in the event your ambient temps rise above 104. But as for your question I believe you would (ideally) go up to the next viscosity grade..in this case an Xw40. This grade would
better resist thinning and stay in grade at such higher temps. That's my understanding of these viscosity/ambient temp charts anyhow. Maybe someone else has something to add or correct if I got it wrong.