polymer causes more thickening at high temperatures, giving the oil "multigrade" characteristics. This is iliuszrated schematically in Fig.3. "Multigradc" oils fall into a higher viscosity band at lO0‘°C than that of the straight "W" grade oil. For cxampic, a SAE 10W4O oil has a viscosity of less than 3500 CP at -20°C but must have a viscosity greater than 12.5 cSt (about 10.5 CP) at 100°C. rather than 4.1 cSt for a SAE IOW oil