PROPERTIES

MIL-G-25537C

TYPICAL

Oil type

–

Mineral

Thickener type

–

Calcium Soap

Base oil viscosity

mm²⁄S

@ 40°C

–

12.5

@ 100°C

–

3.1

Useful operating temperature

range

°C

–

–54 to +93

Drop point

°C

140 min

148

Worked penetration @ 25°C

265 to 305

273

Unworked penetration @ 25°C

200 min

269

Bomb oxidation pressure

drop @ 99°C

100 hrs

MPa

0.0345 max

0.0207

400 hrs

MPa

0.1378 max

0.0689

Oil separation @ 100°C,

30 hrs

% m

5.0 max

1.5

Water resistance test loss

% m

–

7.2

Evaporation loss 22 hrs

@ 100°C

% m

7.0 max

5.6

Antifriction bearing performance

@ 93°C

hrs

–

1700+

Copper corrosion 24 hrs @

100°C

Must pass

Passes

Bearing protection 2 days @ 52°C

Must pass

Passes

Colour

–

Tan

U.S.

Approved MIL – G -25537C

British

Approved DEF STAN 91- 51

French

–

Russian

–

NATO Code

G-366

Joint Service Designation

XG-284