Originally Posted By: tinmanSC
Most people don't understand the SAE grade system. It's confusing and non-intuitive.
Yep. There are 0w-30 and 5w-30 HDEOs that are substantially thicker by HTHS than are many 10w-30 PCMOs out there. Aside from paying attention to HTHS (if it's published), one needs to notice if the oil has an ILSAC rating or not. If the 0w-30, 5w-30, or 10w-30 doesn't have an ILSAC rating, there's probably a reason for it, and viscosity may be on the high end of the scale, along with ZDDP.