A particular requirement of aviation greases is the need to resist high temperature stresses, while providing excellent starting and low torque at low-temperature. To meet this combination of needs ExxonMobil product formulation scientists chose synthetic hydrocarbon base oils for Mobilgrease 28 because of their low volatility, exceptional thermal/oxidative resistance, and superb low-temperature capability. Formulators chose specific thickener chemistry and a proprietary additive combination which helps maximize the benefits of the synthetic base oils.

Mobilgrease 28 meets the requirements of key military and commercial aviation specifications and has built up a superb reputation for performance and reliability among users around the world.

Mobilgrease 28 provides the following advantages and potential benefits:

Features Advantages and Potential Benefits
High viscosity index (VI) synthetic base stock with no wax content Allows wide operating temperature range - outstanding high and low temperature performance
  Provides thicker fluid films protecting against wear of equipment parts operating at high temperature
  Causes low resistance during start-up at very low temperatures
Excellent protection against wear and corrosion Superb bearing protection and helps extend bearing life and reduce bearing replacement costs
Extreme-pressure protection characteristics Avoids excessive wear, even under shock load
High thermal/oxidative stability Long relubrication intervals
High resistance to water washout Maintains excellent grease performance in adverse weather and other water-exposure conditions


Mobilgrease 28 is designed for the lubrication of plain and rolling bearings at low to high speeds, and splines, screws, worm gears, and other mechanisms where high friction reduction, low wear, and low lubricant friction losses are required. The recommended operating temperature range is -54ºC to 177ºC (-65ºF to 350ºF) with appropriate relubrication intervals.

Mobilgrease 28 is recommended for use in landing wheel assemblies, control systems and actuators, screw jacks, servo devices, sealed-bearing motors, oscillating bearings, and helicopter rotor bearings on military and civil aircraft. Subject to equipment manufacturer approvals, it can also be used on naval shipboard auxiliary machinery and where superseded specifications MIL-G-81322 (WP), MIL-G-7711A, MIL-G-3545B, and MIL-G-25760A are recommended.

Mobilgrease 28 is also recommended for industrial lubrication, including sealed or repackable ball and roller bearings wherever extreme temperature conditions, high speeds, or water washing resistance are factors. Typical industrial applications include conveyor bearings, small alternator bearings operating at temperatures near 177ºC (350ºF), high-speed miniature ball bearings, and bearing applications where oscillatory motion, and vibration create problems.

Mobilgrease 28 is qualified by the U.S. Military under Specification MIL-PRF-81322, General-Purpose, Aircraft, and Specification DOD-G-24508A (Navy) for shipboard auxiliary machinery. It is a U.S. Military Symbol WTR and NATO Code Number G-395 grease.


Mobilgrease 28 Is Approved Against Quality Level
MIL-PRF-81322G X  
DOD-G-24508A, Amendment 4   X
NATO G-395 X  

Typical Properties

  Test Methods Mobilgrease 28 Typicals (1) MIL-PRF-81322 Limits
NLGI Grade   1 1/2  
Thickener Type   Clay (non-soap)  
Color Visual Dark Red  
Structure Visual Smooth, buttery  
Dropping Point, ºC (ºF) ASTM D 2265 307 (584) 232 (450) min
Viscosity of Base Oil, cSt ASTM D 445    
at 40ºC   30  
at 100ºC   5.7  
Low Temp. Torque at -54ºC (-65ºF), Nm (g-cm) ASTM D 1478    
Starting   0.43(4400) 0.98 (10,000) max
Running, after 1 Hr   0.05 (510) 0.098 (1,000) max
Penetration @ 25ºC (77ºF), 60 Stoke Worked, mm/10 ASTM D 217 293 265-320
Extended Worked Penetration Stability, 100,000 Strokes, mm/10 FTM 313 303 350 max
Oil Separation, 30 Hrs at 177ºC, wt % ASTM D 6184 3.5 2.0 - 8.0
Evaporation Loss, 22 Hrs at 177ºC, wt % ASTM D 2595 6 10 max
Copper Strip Corrosion, 24 Hrs at 100ºC ASTM D 4048 1b 1b max
Four-Ball Wear, Scar dia, mm ASTM D 2266 0.6 0.8 max
Load Wear Index, kgf ASTM D 2596 40 30 min
Rust Protection, 48 Hrs at 125ºF, › 1mm dia Corrosion Spots ASTM D 1743 Pass 0
Water Washout, 1 Hr at 41ºC, wt % ASTM D 1264 1 20 max
High Temperature Performance, Hrs at 177ºC ASTM D 3336 (modified) Pass 400 min
Oxidation Stability, pressure drop in kPa ASTM D 942    
100 Hrs at 99ºC   Pass 83 max
500 Hrs at 99ºC   Pass 172 max
Dirt Count, Particles/mL FTM 3005    
25-74 Micron   Pass 1000 max
75 Micron or Larger   0 0
Oscillation Friction and Wear, Scar Dia, 35,000 cycles, 90º Angle, Aluminum Bronze Block, mm Modified ASTM D 3704 Pass 6.35 max
Rubber Swell, L Type Synthetic, 1 week at 70ºC (158ºF), vol % FTM 3603 6 10 max
(1) Typical properties are typical of those obtained with normal production tolerance and may vary slightly, while remaining within specified limits.      


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Why did you choose this?
The Lubricant Store Store
put thin coat on buss bar ends for wind turbine towers
richard w on Jan 4, 2019
easy access and reliable.
Rowena J on Oct 17, 2018
put thin coat on buss bar ends for wind turbine towers
richard w on Jan 4, 2019
JOHN M on Nov 12, 2018
easy access and reliable.
Rowena J on Oct 17, 2018
We use it to lubricate linear bearings.
Tom L on Oct 2, 2018
This mobile grease was recommended by Switch Rep. Thanks Steve
Steve T on Oct 1, 2018
Good product
Angie S on Aug 7, 2018
Recommended grease for ball screws on a CNC router.
Don P on Jul 23, 2018
Pascor Atlantic Recommended
John H on May 17, 2018
Specified by Naval Shipyard.
Jim C on May 10, 2018
JOHN M on Nov 12, 2018
We use it to lubricate linear bearings.
Tom L on Oct 2, 2018
will this grease interact negatively with the Mobil Blue Polyurea (Mobil Polyrex EM) that we are currently using?
A shopper on Jul 9, 2018
BEST ANSWER: According to Exxon Mobil lab testing, Mobilgrease 28 and Mobil Polyrex EM are borderline compatible. One of the major differences identified is the variance in viscosity with Mobilgrease 28 being lighter at 30 centipoise vs Polyrex EM at 150 centipoise. This means that there should not be a negative interaction between the two greases, however, it is highly recommended that for best results and as an industry standard, purging of old grease from equipment should be done before converting from one grease to another.