Hi Kevin,

There is a viscosity value for HTHS ranging say from 2.9 to 3.6 in cP. What exactly is cP? I guess what I'm asking, what do the letters stand for?

I see Amsoil has a 3.51 cP rating for its synthetic 10W-30 in an '03 ASTM D-4683 test. That would m... Login to read more.