Mobil Avrex™ S Turbo 256

Turbo engine of an aircraft

Mobil Avrex™ S Turbo 256 gas turbine lubricant is a combination of a highly stable synthetic base fluid and a unique chemical additive package.

The combination provides outstanding thermal and oxidative stability to resist deterioration and deposit formation in both the liquid and vapor phases, as well as excellent resistance to foaming. It is uniquely suited for use when extreme low temperatures restrict the use of higher viscosity engine oils.

In extensive laboratory testing and in-flight performance, Mobil Avrex S Turbo 256 exhibits excellent bulk oil stability at temperatures up to 176 degrees Celsius (350 F). The evaporation rate at these temperatures is low enough to prevent excessive loss of volume.

Data sheets

Technical Resources


Mobil Avrex S Turbo 256 is recommended for aircraft gas turbine engines incommercial and military service, particularly where start-up temperatures arebelow -40°C (-40°F). The product is approved against U.S. MilitarySpecification MIL-PRF-7808, Grade 3, and by the following engine and accessorymanufacturers:

Engine and Accessory Approvals

Approved in equipment specifying 3 centistokes, MIL-PRF-7808 (latest revision)lubricants. Mobil Avrex S Turbo 256 is compatible with other synthetic gasturbine lubricants meeting MIL-PRF-7808 or MIL-PRF-23699 Specifications.However, mixing with other products is not recommended because the blendwould result in some loss of the performance characteristics of Mobil Avrex STurbo 256. The product is compatible with all metals used in gas turbineconstruction, as well as with F rubber (Viton A), H rubber (Buna N), and FVMQrubber (fluorosilicone).


Uniquely suited for use when extreme low temperatures restrict the use of higher viscosity engine oils.

Typical Properties

Avrex S Turbo 256 MIL-PRF-7808 Grade 3 Requirements
Product Number 49423-7 -
cSt at 100°C (212°F) 3.3 3.0 min
cSt at 40°C (104°F) 13.3 11.0 min
cSt at -51°C (-60°F) after 3 hr 10,459 17,000 max
cSt at -51°C (-60°F) after 72 hr 10,495 17,000 max
Flash Point, °C (°F) 224 (435) 210 (410) min
Fire Point, °C (°F) 256 (493) -
Pour Point, °C (°F) -60 (-75) -
Specific Gravity, 15/15°C (60/60°F) 0.9634 -
TAN, mg KOH/g 0.03 0.30 max
Evaporation Loss, %
6.5 hr at 204°C (400°F) 19.6 30 max
Foam, volume/collapse time
Static, ml/sec 20/6 100/60 max
Dynamic, ml/sec pass 100/60 max
Rubber Swell, %
H Rubber, 168 hr at 70°C (158°F) 28.6 12-35
F Rubber, 72 hr at 175°C (347°F) 19.1 2-25
FS Rubber, 72 hr at 150°C (302°F) 10.6 2-25

Health and Safety

Based on available information, this product is not expected to produceadverse effects on health when used for the intended application and therecommendations provided in the Material Safety Data Sheet (MSDS) arefollowed. MSDS's are available upon request through your sales contractoffice, or via the Internet. This product should not be used for purposesother than its intended use. If disposing of used product, take care toprotect the environment.

Hamilton Sundstrand/UTAS APS 500
Hamilton Sundstrand/UTAS APS 1000
Hamilton Sundstrand/UTAS APS 2000
Hamilton Sundstrand/UTAS APS 2300
Hamilton Sundstrand/UTAS APS 2600
Hamilton Sundstrand/UTAS APS 3200
Pratt & Whitney Canada 901
Pratt & Whitney Canada 980
Severe operating conditions
Deposit control
Foaming resistance
Low temperature viscosity
MIL-PRF-7808, Grade 3
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