Originally Posted by
LR3 Disco Owner
And there's the kicker, ISO 4925 Class 6 states that the viscosity has to be at or below 750 whereas Class 4 is at or below 1800.
Now the ISO standard also says that Super DOT 4 should be Class 6, but both the Nulon and the Penrite don't meet the Class 6 specification with viscosities of 1231 and 1147 respectively, instead they just list that they meet ISO 4925 and don't mention the Class, could this be to deliberately mislead, as people would rightly assume that since it is Super DOT 4 that it should be Class 6?
I'd be interested to see a graph of the viscosity against temp to see how they compare at around 0 degrees as that's probably more applicable here than -40!