Mobil Grease 33 All-Temperature Aircraft Grease for Extreme Operating Environment

Aircraft maintenance is a study in extremes: commercial and military (especially military) aircraft operate in all weather, in all climates, at all times of the day or night. There are no alternatives; when a military mission is cut short, it has to be executed no matter the physical conditions. 

The systems have to perform from the coldest overnights in Alaska to the muggy salt air of Guam and Japan, and then to the stifling heat and sandstorms of the Persian Gulf, and everything in between. Mobil Grease 33 is ExxonMobil’s state-of-the-art lithium-complex aviation grease, engineered to protect aircraft components across a wide range of environments. 

Available through GSA Advantage from Greenwood Aerospace, Mobil Grease 33 is a high-performance, NLGI 1-2 aviation grease formulated with a 100% poly-alpha-olefin (PAO) base oil and enhanced by a proprietary additive package. Let’s take a look at Mobil Grease 33 and what it is made for, and how you can easily procure it for your maintenance teams!

Note: This article is part of a series on ExxonMobil's aviation-grade greases. For the whole series, make sure to start with “The Greenwood Aerospace Guide to ExxonMobil Aviation Greases and Gear Lubricants.”

Why All‑Temperature Grease Is Critical for Aviation

Extreme thermal cycles are standard fare for fixed-wing and rotary aircraft: frigid ground starts, high-altitude low-temperature climbs, and prolonged high-temperature cruises in hot climates. Mineral-based greases are prone to thinning, oxidization, and sludge buildups in these most unforgiving environments. 

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Mobil Grease 33 is a PAO base oil with a high viscosity index of 144 and low volatility, making it a safe product that maintains film thickness across the full operating temperature range. The lithium-complex thickener adds structural stability and water-washout resistance. This results in a grease that stays where it needs to be, protects components, and reduces demand for frequent lubrication. 

Product Overview: Mobil Grease 33

Let’s take a quick look at Mobil Grease 33. For a full product breakdown, see the product page and PDS; for safety information, read the SDS. 

  • Formulation: 100% PAO base oil + lithium-complex metallic-soap thickener + advanced additive system
  • Compliance: MIL-PRF-23827C (Type I), NATO G-354
  • Viscosity Grade: 68 (ASTM D445) – 66 cSt @ 40 °C, 10.3 cSt @ 100 °C
  • Viscosity Index: 144 (sustained performance from arctic to desert)
  • Consistency: NLGI 1-2 (smooth, lump-free)
  • Manufacturer part number: 110373 (EXXONMOBIL 110373 MOBIL33-35-2L)
  • Packaging options on GSA:

Key Features & Benefits

Key features define how a grease or industrial lubricant performs under specified conditions. Of course, always consult technical data for your particular airframes 

  • High Viscosity Index & Low Volatility: maintains film thickness from –100°F to 250°F; minimal oil loss due to evaporation.
  • Outstanding Thermal & Oxidative Resistance: PAO base oil resists degradation at high temperature, extending grease and part service life.
  • Water‑Washout Resistance: lithium‑complex thickener and additive system keep the grease stable in adverse weather and water‑exposed environments.
  • Low‑Temperature Mobility & Pumpability: excellent low‑temp torque values (starting ≤ 1.00 Nm, running ≤ 0.10 Nm at –100 °F).
  • High Load‑Carrying Capacity & Extreme‑Pressure Characteristics: superior wear protection, high load wear index (≈ 110 kgf), Timken OK Load ≈ 55 lbf, and excellent four‑ball wear performance (0.4 mm scar).
  • Corrosion & Rust Prevention: additive package provides rust protection (ASTM D 1743) and passes copper‑strip and AMS 4640 aluminum-bronze corrosion tests.
  • Storage Stability & Low Oil Separation: grease structure remains intact after 30 h at 100 °C; oil separation ≤ 5 %.
  • Compatibility with Elastomers & Thermoplastics: proven with nitrile, Hytrel, Delrin, PTFE, Nylatron, etc., ensuring no swelling or degradation.

Technical Specification Table–Mobil Greases

Property Test Method Typical Result
Viscosity Grade–68
Viscosity @ 40 °CASTM D44566 cSt
Viscosity @ 100 °CASTM D44510.3 cSt
Viscosity IndexASTM D2270144
Dropping PointASTM D2265165 °C (329 °F)
Low-Temperature Torque (-73 °C) DEF STAN 05-50 / ASTM D1478 Start ≤ 1.00 Nm, Run ≤ 0.10 Nm
Low-Temperature Torque w/ 10 % Water DEF STAN 05-50 / ASTM D1478 Start ≤ 0.67 Nm, Run ≤ 0.09 Nm
Penetration (25 °C) ASTM D217 Unworked: 200 mm/10; 60 strokes: ≈ 285 mm/10
Oil Separation (30 h @ 100 °C) ASTM D6184 ≤ 5 %
Evaporation Loss (22 h @ 100 °C) ASTM D2595 ≤ 2 %
Evaporation Loss (500 h @ 121 °C) ASTM D2595 ≈ 8.7 %
Copper Strip Corrosion (24 h @ 100 °C) ASTM D4048 1B (pass)
Four-Ball Wear (1200 rpm / 40 kg / 1 h / 75 °C) ASTM D2266 0.4 mm scar
Load Wear Index ASTM D2596 110 kgf
Timken OK Load ASTM D2509 55 lbf
Rust Protection (48 h @ 125 °F) ASTM D1743 0 spots (pass)
Water Washout (1 h @ 38 °C) ASTM D1264 ≤ 20 %
Water Washout (1 h @ 79 °C) ASTM D1264 ≤ 6 %
High-Temperature Performance (121 °C) ASTM D3336 ≥ 2,200 min
Oxidation Stability (99 °C, 100 h) ASTM D942 ≤ 70 kPa
Oxidation Stability (99 °C, 500 h) ASTM D942 ≤ 105 kPa
Fretting Wear ASTM D4170 0.6 mg
Dynamic Bearing Life BMS 3-33-8.2 Pass
Navy Gear Wear Test FTM 335 2.3 kg load ≤ 2.5 max; 4.5 kg load ≤ 3.5 max
Elastomer Compatibility (70 °C, 168 h) FTM 3603 NBR +12.6 % vol, etc.
Thermoplastic Compatibility (100 °C, 70 h) ASTM D4289 Hytrel +0.5 % carbon black, etc.

Typical Applications & Compatibility

Mobil Grease 33 is a multipurpose grease for use and applications all across the aircraft. The most common uses are:

  • Landing‑gear and wheel‑well bearings which are high‑load, high‑temperature applications.
  • Actuator and servo‑gear assemblies where precision motion is standard and low start-up torque performance is critical. 
  • High‑speed bearings for turbine accessories and auxiliary gear boxes (not recommended for wheel bearings; use Mobil Grease 28 for these).
  • General airframe lubrication for hinges, control-surface linkage, and even instrument bay components. 

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Mobil Grease 33 is compatible with most seal materials, including fluorocarbon, polyacrylate, polyurethane ether, nitrile, and silicone, so there is little concern about seal deterioration if they come into contact with Mobil Grease 33. 

Procurement Through GSA Advantage

We have made the federal and military procurement process as easy as possible by working through the GSA Schedule and listing this product (and hundreds of others) on GSA Advantage. Our process is this:

  1. Click the View on GSA Advantage link for the desired packaging (13.4 oz cartridge, 55 gal drum, or 35.2 lb pail – part # 110373).
  2. Add the item to your cart or submit a quote request.
  3. Complete the purchase using your agency’s GSA contract number.

You can order this product directly from our product links:

This makes your budget much easier to populate and obtain approval from senior management; there is no guesswork, and the price is listed with no hidden charges.

For bulk orders, urgent shipments, or technical support, email gsasales@greenwood.aero or call our office at 833-472-3289 (833-GSA-EBUY). We are uniquely positioned to help as a HUBZone-certified & Native-American owned small business, and promptness is a top priority. 

The ExxonMobil Mobil Grease Series of Greases Articles 

This article is part of The Greenwood Aerospace Guide to ExxonMobil Aviation Greases and Gear Lubricants, a comprehensive series designed to help aviation maintenance and procurement professionals choose the right ExxonMobil lubricants for their missions. Explore related articles, including Mobil Grease 28: Synthetic Aircraft Grease, Mobil AGL Gear Lubricant: Synthetic Helicopter Gear Oil, and Mobil Grease 28 vs. AGL: Matching Grease and Gear Oils to Aircraft Missions, or visit Greenwood Aerospace on GSA Advantage to view the full ExxonMobil lineup.