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Exxon Mobil Mobilgrease 28 Aviation Lubricant

Exxon Mobil Mobilgrease 28 Aviation Lubricant

Lubrication is a necessary job when maintaining the smooth functioning of moving parts. Mobilgrease 28 aviation lubricant provides superior protection for such a task.

Made with polyalphaolefin synthetic compounds (known in the petro industry simply as PAO) and a non-soap, organo-clay thickener, this anti-wear red grease endures despite the everyday stresses encountered by aircraft. Mobilgrease 28 reduces frictional drag and does it very well.

Using Mobilgrease 28 can help increase the lifespan of your bearings, saving you money over time. How? Its special formulation of PAO and clay thickener offers water-resistance as well as low traction and low running torque. Once applied, any abrasion that can cause high temperature is reduced. All the while, this grease maintains its stability while protecting against the wear and tear associated with friction.

This product is designed specifically for aircraft and aviation applications. It can be used on landing wheel assemblies, rotor bearings, screw jacks and oscillating bearings. It's so versatile that it works well within the components of control systems, actuators and also servo devices.

If you have searched our site, then you know standards are important to us. Mobilgrease 28 conforms to U.S. Military Specification, MIL-G-81322E. Its worldwide use for more than three decades demonstrates its reliability and continued high-quality performance.

We offer Mobilgrease 28 aviation lubricant in several container sizes so you never have to order too much. Choose between convenient 13.7-ounce tubes, 4.4-pound pails and 35-pound buckets. Looking for something larger? We offer 110.2-pound drums as well. For more information examine the rest of this page including the MSDS for safe use and handling of this product.


  • NATO Specification: G-3952
  • US Military Specification: NLGI Grade 1
  • US Military Specification: DOD-G-24508A, Amendment 4
  • US Military Specification: MIL-G-81322 Grade B
  • US Military Specification: MIL-PRF-81322G
  • Applications
    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 -55°C to 180°C with appropriate relubrication intervals.

    Mobilgrease 28 meets the quality level of military specifications MIL-G-81322 for wide temperature range aviation service and is approved under DOD-G-24508A for shipboard service. Specific military and civil aviation applications include:

  • Landing wheel assemblies
  • Control systems, screwjacks, servo devices, actuators, sealed-bearing motors and oscillating bearings
  • Helicopter rotor bearings on aircraft and on naval shipboard auxiliary machinery
  • It also can be used where superseded specifications MIL-G-81322 (WP), MIL-G-7711A, MIL-G-3545B, and MIL-G-25760A may be called for
  • Mobilgrease 28 also is 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 177°C
  • High-speed miniature ball bearings, and bearing situations where oscillatory motion, vibration, and fretting create problems
  • Features

    Mobilgrease 28 is one of many Mobil branded PAO-based products recognized around the world for innovation and outstanding performance. Synthetic products like Mobilgrease 28 represent ExxonMobil's, continuing commitment to using advanced technology to provide outstanding products. Close contacts between ExxonMobil scientists and application specialists and key equipment builders ensure that our products meet the needs of the latest aviation equipment designs.

    Good resistance to high temperature stresses and excellent starting and low torque at low-temperature are two of the most important requirements of aviation greases.To meet this combination of needs our product formulation scientists chose proprietary synthetic base oils for Mobilgrease 28 because of their exeptional thermal/oxidative resistance potential, and superb low-temperature capability. Our formulators chose specific thickener chemistry and a prorietary additive combination which would maximize the benefits of the synthetic base oils.

    Mobilgrease 28 meets the requirements of key military and commercial aviation specifications and has built up an excellent reputation for performance and reliability among users around the world. Mobilgrease 28 provides the following advantages and potential benefits:

    Features Advantages and Potential Benifits
    High viscosity index base stock with no wax content Very wide operating temperature range - outstanding high and low temperature performance
      Excellent film protection at high temperatures
      Minimum resistance to start-up at extremely low temperatures
    Low traction base oil Low sliding friction and reduced heat build-up
      Potential for energy savings
    Excellent protection against fretting wear and corrosion Superb bearing protection and extended bearing life and reduced bearing replacement costs
    Extreme-pressure characteristics Avoids excessive wear, even under shock load
    High thermal/oxidative stability Extended relubrication intervals
    High resistance to water washout Maintains excellent grease performance in adverse weather and other water-exposure conditions

    Test Methods

    Mobilgrease 28 (1)

    MIL-PRF-81322 Limits
    NLGI Grade  1 1/2  
    Thickener Type  Clay (non-soap) 
    ColorVisualDark Red  
    StructureVisualSmooth, buttery 
    Dropping Point, ºC (ºF)ASTM D 2265315 (599)232 (450) min
    Viscosity of Base Oil, cSt ASTM D 445  
    at 40ºC 29.3 
    at 100ºC 5.6 
    Low Temp. Torque at -54ºC (-65ºF), Nm (g-cm)ASTM D 1478  
    Starting 0.83 (8500)0.98 (10,000) max
    Running, after 1 Hr 0.08 (800)0.098 (1,000) max
    Penetration @ 25ºC (77ºF), 60 Stoke Worked, mm/10ASTM D 217 295 265-320
    Extended Worked Penetration Stability, 100,000 Strokes, mm/10FTM 313302 350 max
    Oil Separation, 30 Hrs at 177ºC, wt %ASTM D 61842.52.0 - 8.0
    Evaporation Loss, 22 Hrs at 177ºC, wt %ASTM D 2595610 max
    Copper Strip Corrosion, 24 Hrs at 100ºC ASTM D 4048Pass1b max
    Four-Ball Wear, Scar dia, mm ASTM D 22660.50.8 max
    Load Wear Index, kgf ASTM D 25964230 min
    Rust Protection, 48 Hrs at 125ºF, › 1mm dia Corrosion SpotsASTM D 1743 Pass0
    Water Washout, 1 Hr at 41ºC, wt % ASTM D 1264120 max
    High Temperature Performance, Hrs at 177ºCASTM D 3336Pass400 min
    Oxidation Stability, pressure drop in kPa ASTM D 942  
    100 Hrs at 99ºC Pass83 max
    500 Hrs at 99ºC Pass172 max
    Storage Stability, 6 months at 38ºCFTM 3467PassPass
    Dirt Count, Particles/mLFTM 3005  
    25-74 Micron  Pass1000 max
    75 Micron or Larger 00
    Oscillation Friction and Wear, Scar Dia, 35,000 cycles, 90º Angle, Aluminum Bronze Block, mmModified ASTM D 3704 Pass 6.35 max
    Rubber Swell, L Type Synthetic, 1 week at 70ºC (158ºF), vol %FTM 3603 6 10 max
    (1) Values may vary within modest ranges   
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    13.7 oz Cartridge
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    4.4 lb Can
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