| SAE Viscosity Grade |
Low temperature (°C) | High temperature (100 °C) | |||
| Cold Cranking viscosity (cP, max) b |
Pumping viscosity (cP, max, no yield stress) c |
Min viscosity d(cSt) | Max viscosity d(cSt) | High shear viscosity(cP), at 150°C and 106s-2, mine | |
| 0W | 6200 at - 35 | 60,000 at - 40 | 3.8 | - | - |
| 5W | 6600 at - 30 | 60,000 at - 35 | 3.8 | - | - |
| 10W | 7000 at - 25 | 60,000 at - 30 | 4.1 | - | - |
| 15W | 7000 at - 20 | 60,000 at - 25 | 5.6 | - | - |
| 20W | 9500 at - 15 | 60,000 at - 20 | 5.6 | - | - |
| 25W | 13000 at - 10 | 60,000 at - 15 | 9.3 | - | - |
| 20 | - | - | 5.6 | < 9.3 | 2.6 |
| 30 | - | - | 9.3 | < 12.5 | 2.9 |
| 40 | - | - | 12.5 | < 16.3 | 2.9f |
| 40 | - | - | 12.5 | < 16.3 | 3.7g |
| 50 | - | - | 16.3 | < 21.9 | 3.7 |
| 60 | - | - | 21.9 | < 26.1 | 3.7 |
| |||||
Multigrade oils are used for year round service in automotive engines except some 2 stroke diesel engines. Oils of this type generally require the use of VI improvers in conjunction with mineral or synthetic basestocks.
HT/HS viscosities are measured at 150°C under shear stresses similar to engine bearings. The HT/HS performance indicates temporary stability of VI improvers used to formulating multigrade engine oils. For instance, according to the SAE classification, an oil must achieve 3.7 cp of HT/HS value or higher in order to be classified as 15W-40 viscosity grade. The thinner the oil the lower the number.
At low temperature, the high shear rate viscosity is measured by ASTM D 5293, a multitemperature cold cranking simulator(CCS) method. The low temperature, low shear rate viscosity is measured by ASTM D 4684. Both methods simulate working conditions of engine starting up and engine oil pumpability respectively at low temperatures.
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