Open cast mine shot from above

Extended Oil Life

Up to 10,000 hours TOST Life


Shell Tellus S4 VE fluid is an advanced-performance, shearstable hydraulic fluid with strong thermal and oxidative stability. In addition to meeting standard industry and equipment manufacturers’ specification requirements, Shell Tellus S4 VE exceeds the 10,000 hours maximum duration that can be measured in the industry-standard turbine oil stability test (TOST).


TOST is an industry test to help differentiate a hydraulic oil’s life in operation.

Although TOST life is not equal to a hydraulic oil’s operating life, it is an important test to help describe the durability of an oil in the field, especially when exposed to environmental stress and elements.

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