Originally posted by Callisa:
HTHS is one of the most missunderstood characterisrics of oil. Having an extreme high HTHS value gives no security at all. I don't understand why people don't understand this.
I would like to know more about this. It seems to me that, since HTHS is a measure of viscosity, one would want it to be within a reasonable range, not too high, not too low. I would suspect diesels would need a higher HTHS than gasoline engines which have excellent durability with oils having HTHS viscosity in the range of about 3.0 to 3.6 cSt. The new 5w20 oils with HTHS below 3.0 do make me hesitant, but for now my older vehicles do not spec such thin oils.