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Mobil Jet Oil II vs Mobil Jet Oil 254: A Complete Turbine Oil Guide
The lifeblood of all turbine engines is in the oil. Oil quality, oil durability, and proper lubrication strategies are the key metrics to extend engine life and guarantee reliability over the lifecycle of the engine.
Mobil Jet Oils are your first line of defense against the harmful effects of aging, oxidation, and thermal instability. Suitable for commercial and military service, Mobil turbine engine oil is made for the harshest conditions on earth.
Greenwood Aerospace is committed to making the procurement process for Mobil Jet Oils as painless as possible by selling to federal procurement specialists and military buyers through GSA Advantage. If you are ready to buy, visit our quick links below:
Mobil Jet Oil II:
- Quart Case (24 qt): GSIN 11000125246433
- Pallet (960 qt): GSIN 11000125246432
- Quart Case (24 qt): GSIN 11000125246402
Mobil Jet Oil 254:
- Quart Case (24 qt): GSIN 11000069837277
- Quart Case (24 qt): GSIN 11000125246137
- 55 Gallon Drum: GSIN 11000125246431
Otherwise, let’s take a look at Mobil turbine oils and how best to use them in turbine aircraft engines and accessories!
Turbine Oils and what MIL-PRF-23699 standards mean
Mobil Jet Oil II & Mobil Jet Oil 254 both do exceptionally well at remaining viscous, even when temperatures get really wild. Mobil Jet Oil II operates between -40°C and 204 °C. While that is a wide range, Mobil Jet Oil 254 pushes that right up to -40°C to 232°C, and even more extreme high-temperature jobs aren't going to be a problem for it.
The difference in quality comes down to their MIL-SPEC classification. Mobil Jet Oil II meets only MIL-PRF-23699, the standard, and Mobil Jet Oil 254 goes further by qualifying for the high-thermal-stability (HTS) classification of MIL-PRF-23699. These standards help the government ensure its purchasing protocols deliver the high-quality products it needs.
What really sets Mobil Jet Oil 254 apart, though, is its advanced formula, which helps reduce the buildup of old oil that can damage engines. Specifically, it does this by reducing bulk oil oxidation by up to 50% compared to conventional lubricants and by providing 50°F better deposit control than type II. When you put it all together, it means longer durations between oil changes and less need for expensive maintenance.
Thermal and Oxidation Stability
Both Mobil Jet oils have excellent thermal and oxidation stability and are designed to effectively lubricate turbine engines across a wide temperature range, from extreme cold to extreme heat. Mobil Jet Oil II operates effectively between -40°C to 204°C (-40°F to 400°F), while Mobil Jet Oil 254 extends this range to -40°C to 232°C (-40°F to 450°F).
Mobil Jet Oil 254 reduces bulk oil oxidation by up to half compared to other standard Type II oils, and increases deposit control by up to 50°F. Mobil Jet Oil 254 is a third-generation oil that provides high thermal stability and resists deterioration and deposit formation in turbine engines, with greater effectiveness than standard formulations.
Load-Carrying and Lubrication Capabilities
Both Mobil Jet Type II oils have good load-carrying capacity, corrosion resistance, and low-temperature viscosity. These oils are well-suited for severe conditions thanks to their synthetic base-stock viscosity and are not affected by viscosity-index additive shear.
Military Specifications and Standards
The MIL-PRF-23699 standard is what the U.S. Military requires for synthetic lubricating oils for aircraft gas turbine engines. It effectively replaced the older MIL-L-23699 standard, and it breaks things down into three main categories: Standard (STD), Corrosion Inhibiting (C/I), and High Thermal Stability (HTS). This spec outlines the all-important performance requirements, including thermal stability, oxidation stability, corrosion resistance, and compatibility with various engine materials.
When this oil is operating properly, it maintains a viscosity of 5 centistokes at 100°C, and you can count on it to perform its duties over a wide temperature range: from -40°C to 204°C (-40°F to 400°F). It has thermal stability in spades, capable of holding its own in engines that crank out speeds up to 14,000 RPM or operate at altitudes up to FL450. If you're looking at the C/I classification, it provides additional corrosion protection in damp environments or when left idle for extended periods.
Unique Chemical Additive Packages
Each of these oils is formulated with a chemical additive package to enhance engine efficiency and longevity by reducing carbon deposits and sludge. Mobil Jet Oil 254’s advanced formula is purpose-built to resist carbon coking and deposit formation.
Mobil Jet Oil II: The High Performance Standard
Mobil Jet Oil II is the original Type II oil on the market, and now has more than five decades of use and has accumulated an incredible five billion flight hours of on-wing time.
Mobil Jet Oil II is a legendary Type II, second-generation turbine oil is a no-hassle solution for turbine engines.
Key Performance Features
- Outstanding thermal and oxidative stability to resist deterioration and deposit formation in both liquid and vapor phases.
- Excellent wear and corrosion protection that extends gear and bearing life.
- Superior load-carrying ability from synthetic base stock viscosity
- Excellent resistance to foaming maintains film strength under rigorous operating conditions
- High specific heat ensures good heat transfer from oil-cooled engine parts
- Low pour point (-59°C typical) eases start-up in low ambient temperature conditions
- Excellent elastomer compatibility helps maximize component life and minimize oil consumption.
Applications
Mobil Jet Oil II is used in roughly half of all turbine-powered aircraft worldwide. That is an absolutely astonishing statistic, but it holds up. It is a MIL-PRF-23699-STD-approved turbine engine oil suitable for all military aircraft that specify this standard.
OEM and Builder Approvals
Mobil Jet Oil II carries an extensive range of approvals from major engine manufacturers:
- Honeywell/Lycoming-Turbine engine
- Rolls-Royce/Allison Engine Company
- CFM International
- General Electric Company
- Pratt & Whitney Group
- Pratt & Whitney Canada
- Rolls-Royce Limited
- SNECMA
- Turbomeca
- Williams International
Mobil Turbine Oils Available on GSA Advantage
Mobil Jet Oil 254: Third-Generation High Performance
Mobil Jet Oil 254 has been on the market for over three decades and is a third-generation, high thermal stability (HTS) oil. It is a specially-prepared, hindered-ester base stock that is fortified with a proprietary blend of chemicals to reduce deposit control
Superior Performance Characteristics
- Reduces bulk oil oxidation by up to 50% compared to typical Type II lubricants. Lower oxidation results in a cleaner, more efficient operation.
- Deposit control capability 50°F higher than Type II oils
- Excellent anti-wear and corrosion protection extends seal, gear, and bearing life
- Chemically stable at high operating temperatures, reduces evaporation losses, and lowers oil consumption
- Outstanding low-temperature fluidity with pour point below -54°C (-62°C typical)
- Excellent resistance to foaming maintains film strength under rigorous operating conditions
- Laboratory tests indicate a 40% advantage in higher-temperature bulk oil stability vs. competitive HTS oils tested
Applications and Specifications
Mobil Jet Oil 254 is recommended for:
- Aircraft gas turbine engines of turbo-jet, turbo-fan, turbo-prop, and turbo-shaft (helicopter) types in commercial and military service
- Latest-generation engines requiring MIL-PRF-23699 HTS specification compliance
- Industrial and marine gas turbine engines requiring high thermal stability lubricants
- Aircraft-type gas turbine engines used in industrial or marine applications
OEM and Builder Approvals
The following OEM manufacturers have approved the use of Mobil Jet Oil II and Mobil Jet Oil 254:
Engines:
- Honeywell/Lycoming-Turbines
- Rolls-Royce/Allison Engine Company
- CFM International
- General Electric Company
- International Aero Engines
- Pratt & Whitney Group
- Pratt & Whitney Canada
- Rolls-Royce Limited
- SNECMA
Accessories:
- Honeywell - Auxiliary power units and air cycle machines
- Hamilton Standard - Starters
- Hamilton Sundstrand Corp. - APUs, constant-speed drives, and integrated-drive generators.
Material Safety Considerations
This is a summarization of the SDS for both the Mobil Turbine Oil II and Mobil Turbine Oil 254. For a complete safety briefing and safety data, read the linked documents.
Mobil Jet Oil II and Mobil Jet Oil 254 are synthetic aviation turbine lubricants engineered for use in high-performance gas turbine engines, and both are classified as hazardous under OSHA’s Hazard Communication Standard. According to the SDS for Mobil Jet Oil II, the product contains synthetic esters, including tricresyl phosphate (TCP) and N-phenyl-1-naphthylamine.
It is classified as Toxic to Reproduction (Category 2) and Specific Target Organ Toxicity from Repeated Exposure (Category 2), indicating potential long-term effects on fertility and possible damage to organs such as the blood and kidneys through prolonged exposure.
Mobil Jet Oil 254 carries similar handling and precaution language. It is likewise formulated with synthetic base stocks and performance additives designed to resist oxidation and thermal breakdown at extreme temperatures typical in turbine operation.
Both products require prudent industrial hygiene controls: avoid inhalation of mist or vapor, prevent skin and eye contact, and wear chemical-resistant gloves, protective eyewear, and suitable PPE during handling.
Fire response procedures call for dry chemical, CO₂, foam, or water fog while avoiding direct water jets due to pressure and ignition risk. Spills should be contained with non-combustible absorbents and prevented from entering waterways or drains.
Compatibility with Engine Components
Both Mobil Jet Oil II and Mobil Jet Oil 254 are entirely compatible with all metals used in gas turbine construction. They work seamlessly with commonly used seal materials, including:
- F Rubber (Viton A)
- H Rubber (Buna N)
- Silicone seal materials
Both oils are compatible with other synthetic gas turbine lubricants meeting MIL-PRF-23699. However, mixing with other products is not recommended because the blend would result in some loss of the superior performance characteristics. Also, it is important to remember that any 3rd-generation Type II oil can be used in machinery where 2nd-generation oils like Mobil Turbine Oil II are specified, but not vice versa.
Important Note: When transitioning from Mobil Jet Oil II to Mobil Jet Oil 254, it is recommended to perform the switch at component overhaul to ensure cleanliness.
Choosing Between Mobil Jet Oil II and Mobil Jet Oil 254
Technical Specifications Comparison
How to Procure ExxonMobil Turbine Oils Through GSA Advantage
We decided that the GSA Schedule was the best avenue to source bulk oils from ExxonMobil. Of course, we did not stop with oil; we carry a huge catalog of products from dozens of leading manufacturers. We have a large swatch of ExxonMobil’s lubricants, greases, and oils and list them on GSA Advantage so your federal or military organization can quickly and easily source and buy them. No negotiations, no squabbling over prices. What you see is what you pay, including freight.
GSA Procurement Benefits
Federal buyers can access ExxonMobil Mobil Jet Oils through Greenwood Aerospace's GSA Schedule on GSA Advantage and immediately access nearly 1,000 products, with more added regularly.
Pre-negotiated pricing eliminates lengthy procurement negotiations. You don’t have time for lengthy contracting procedures when your flight operation needs oil for daily flights.
The simplified ordering process complies with federal acquisition regulations. We know how important compliance is, and everything is pre-screened to meet all FARs before it is listed.
You will also get rapid fulfillment from an experienced government contractor. We have over forty years of experience as a contractor, both prime and sub, and have fulfilled contracts with every branch of the military and several federal agencies.
The Greenwood Aerospace Advantage: Your Partner in Aviation
Greenwood Aerospace is committed to being the first and only place you call when it’s time to replenish your bench stock with consumables, oils, greases, and hardware.
Get the ExxonMobil turbine oils (and hundreds of other items) you need with a click or call:
- Email: gsasales@greenwood.aero
- Phone: 833-GSA-EBUY (833-472-3289)
For bulk orders, contact us directly for volume pricing and expedited shipping. Remember, we carry much more than just oils and lubricants.
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